Sometime around August, Nikon annouced two new DSLR models - the D3 and the D300. Since I only look at sub 10K bodies, the one that caught my attention was the D300. The D300 was the replacement model for the D200, which has been in my equipment bag for a couple of years now.
Rather than repeat the press releast from Nikon, you can get it straight from the horse's mouth over here.

Will this be the next item on my must-have list?

Let's go through the differences together:-

Major Features

1. New DX-format CMOS image sensor with 12.3 effective megapixels
My Opinion - This is not necessary a good thing, if the increase is solely in the number of megapixels. What this effectively means is that they are squeezing more pixels into the same old sensor size. Unless they introduce new sensor technology, this will almost certainly result in increased sensor noise.
In any case, more megapixels mean larger pictures, which make archiving more tedious - especially if you shoot raw (NEF format). I used to shoot in RAW - now I'm using my D70 on Medium JPG as standard. If you never intend to Photoshop your photos or edit them with a Raw converter, stick to jpg, as the Medium JPG on the D70 still makes excellent 4R prints.
Lastly, you'll need a larger memory card to shoot at full resolution, as the camera will now hold less shots per card....

2. EXPEED — Nikon’s image processing concept embodied
My Opinion - OK, so it's got a new name (seems to be the marketing strategy to have a high-tech name for the image processor, like Sony's Bionz and Canon's Digic I/II/III). They've got to let the end users what exactly this new chip is good for.

3. High-speed continuous shooting
My Opinion - My D200 shoots at only 5 frames per second max, versus the 6 / 8 fps of the D300. In actual fact, I never ever use this mode - except during the penalty shootout of a football match. In all other situations, I run of space very, very fast (especially if shooting on full size). This is a feature I'd like to have, but will possibly get used less often than I change my car's timing belt....

4. Immediate response
My Opinion - refers to power up and shutter release lag. Not so much an issue for me, as I can still live with my D70's timing. Once the shutter lag is in miliseconds, your reflexes will be more of a determining factor.

5. Scene Recognition System
My Opinion - It's good if you totally rely on the camera's ability to set the correct exposure, ie, put it in "P" mode and fire away. However, once you realize that no camera system is perfect, you'll need to know what the system will do in a given situation so you can compensate the exposure accordingly. This used to be more predictable with the standard center-weighted and spot metering mode. Now, you'll have to either trust the camera, or know how the camera will respond in a given situation, and compenstate accordingly (more of a wild guess). For night scenes, I usually fall back to center-weighted metering to get a more consistent exposure.

6. AF system employing high-density 51-point AF
My Opinion - Regardless of how many sensors my camera has, for my D70 and D200 I only use 1 sensor - the one right in the middle. I have a bad experience of using multiple sensors, as they always lock on to the wrong subject. If the sensor made more sensitive and accurate, I'd welcome this into my stable any time.

7. Picture Control System
My Opinion - Seems to be the new name for the in-camera picture compensation. I used to shoot with low saturation to edit later. You know how tedious that gets, so nowadays I shoot with saturation on maximum with color space III, to get nicely saturated prints right out of the camera. May look appealing to normal consumers rather than pros, but then again, the majority of my viewers are just that - normal consumers. To them, colorful and vibrant are preferred to dull photos (even if the actual scene is itself lifeless and colorless!).

8. Two Liveview modes available
My Opinion - Ever since the days of my Coolpix 5400 and 5700, I have learnt to live life through the viewfinder and not use that big old screen at the back. While it would be nice to have, the reason I use the screen on my coolpix pair is that they allow shooting at odd angles, either way below on the ground, or up over the heads and obstacles of crowd. This gives my photos a unique perspective. With the D300, there's no movable screen, so, even with the higher resolution screen, I'd stick to the viewfinder for a true TTL view.

9. Large, bright viewfinder that achieves 100% frame coverage
My Opinion - Yep, this one is great for reviewing the photos and sucking battery power, but I think I can live with the D200's screen. My D70 allows me to quickly check if anyone blinked - that's also good enough.

10. Durability that will go the distance
My Opinion - Never used a camera still it broke down, so can't comment on this. At this rate, you'll likely upgrade to a new model before the old one dies a natural death anyway....

11. Active D-Lighting
My Opinion - I've always set my contrast on the lowest setting, as I like as much dynamic range as possible. This is why the Fujifilm S5Pro appeals more to me (with exception of the astronomically high price). If this works as advertised, then it's one improvement I'm looking out for.

12. Self-cleaning Sensor Unit for efficient dust reduction
My Opinion - If you only use your one and only kit lens, then this won't mean anything to you. For my case, I've lived without this self-cleaning sensor, so far so good. Having this feature wouldn't hurt.

13. Exclusive Wireless Transmitter WT-4 (optional)
My Opinion - Never imagine using this, as you'll need to have a laptop up and running to receive. Works best in a controlled environment - like a home studio. For me, I work mostly in the field. Lugging around a laptop, or worse, leaving it set up unguarded somewhere public, is not the way I would work. Besides, this will likely be a very expensive accesory.

14. Multi-Power Battery Pack MB-D10 (optional)
My Opinion - The camera body should have this incorporated into the design. This thing costs over RM1000. Paying that much for a battery holder? Sure it's got the second shutter release that allows you to shoot in Portrait mode comfortably, but I don't think I'm the only one who thinks it overpriced. Fortunately, the D300 takes the same batteries as the D200, so some parts are still backward compatible.

Other Features

    * The large top control panel (46 x 20.8mm) features an improved interface with lettering that can be switched to best match shooting conditions;
    * HDMI Output supports HDTV display;
    * Supports GPS devices via optional GPS Adapter Cord MC-35;
    * Retouch Menu provides handy access to Filter Effects, Trimming, Red-eye correction, Image overlay and other in-camera editing functions;
    * Software Suite CD-ROM included.
My Opinion - GPS support with an expensive add-on cable, no doubt. Hopefully, the software bundle will allow for proper NEF processing, unlike the previous software which came with the D200 (which was really, really basic).

Overall view:-
Before making my conclusion, I'd like to state here that I'm not a photographer by profession, so I don't make any money from this. It's more like a hobby. In my company, we have a recreation club and many corporate functions which I have volunteered to serve as the "publicity guy". This gives me plenty of opportunity to use my photographic gear. I also help our my friends for their wedding events, and an odd birthday celebration from time to time.

Having said that, I grade myself into the prosumer category. Somewhere between the novice / family user that snaps family and vacation photos, and the professional photographer who uses this to put food on the table. I don't require (nor can I afford) a 5-figure camera with a 5-figure lens.

From what I can see on paper, the D300 is an incremental improvement over the D200. I don't care much for the 2 megapixel resolution increase, as I'm more interested in the picture quality. Feature-wise, the self-cleaning sensor and live-view stand out - but these are already on the competitors' products, so it's more of and effort to keep up, rather than an innovation to keep ahead of the pack. Given my needs and abilities, there is nothing I would not be able to do with my D200 that I would need a D300 to finish the job.

So, final verdict - I would skip this D300 and wait for the next major innovation from Nikon. At the current rate of production, there'll probably be no stock available for the D300 for months. This is one aspect that Nikon will need to improve in order to go head-to-head against Canon, Sony and Olympus.

Well, the views and opinions voiced here are my own as I am not affiliated with Nikon nor any one of their competitors. If you're considering to get yourself a DSLR, do your extensive homework and try out your choice at the camera shop before you make your purchase.