Would it be worth upgrading to the Nikon D700 from D300 now?

I've been thinking about going full frame, and the Nikon D700 seems to be a pretty good choice. Similar size to D300 and decent price.
I mainly want to get a full frame camera for the high iso performance. I want to stick with Nikon as I just prefer them to be honest, personal choice.

But my question is, is it going to be worth it, what with the D800 just being announced, and also the D7000 high iso performance seems pretty good too. Is the D700 a bit old and outdated?

I read on Ken Rockwells website that you should not buy a new D700 anymore. But I have heard mixed thoughts on Ken Rockwells reviews, so not sure how to take that.

Any thoughts would be appreciated.

Also the D800 has too many megapixels than is needed to be honest. Also I heard that reduces its lowlight capabilities?

It really depend on what you intend on photographing. Ultimately the D700 had an amazing sensor and processor combo producing some of the best low light performances you could get (short of a Pentax K-5), this is something the D7000 can't compare to (as it has a similarly high density sensor to a D800).

Wheras the D700 was firmly targetting at high level amateurs and professionals, the D800 seems to be more specific, and could be considered as a medium format rival, as such the D800 isn't so much of an all rounder that the D700 was. In terms of price, I don't think every single D700 user will try to off load theirs to buy the D800. This combined with growing demand for second hand D700 may keep the market prices relatively high.

However I'd be keen to get rid of the D300 at this point in time, as I can imagine a D300S replacement may cause the bottom to fall out of D300 prices.

Interestingly, from my point of view I'd keep your D300 for a month, sell it. Buy a D7000, and wait for D300S replacement.

I'd get really good lenses instead. Here's the truth. Given really good lenses, I can take the same shot with any of those cameras or my D3s and in 99% of the cases, no one would know the difference. In the pro market you don't get a big choice of cameras, we don't need a choice. For me, I use Nikon so it's the D3s (D4 in 2 months) or D3x, depending on what I do I may want one or the other or both. For the amateur market the companies build cameras for all price points and the amateurs spend days obsessing about cameras. I just started answering questions on this site and I see that the number one question is what camera? IT DOESN"T MATTER MUCH. Very rarely does anyone ask about lenses. Lenses matter way more. If you want low light capabilities do you realize that a really good lens will be able to shoot a picture with 1/4 the light of an amateur lens? That's worth more than the camera.