So talk me out of going to Nikon.

Don't go to the Dark Side.....
It is a path with no way back...

Nikon's gear is usually more expensive, but some of it's lenses perform better than canon.
From your words, it's seems you need / want D700 better than 5D II.

Have been using the D700 for 9 months now .... I would recommend it unless you need video .... Or you could wait for the D800

Was using 40D earlier but when the time to go FF came, I picked D700 for its better (perceived at least) performance in low light, AF (though I use Zeiss 50mm most of the time), built quality and creative lighting system .... So far so good

I am not obsessed about any brand though. For me a camera is a tool and you pick the one that you would think will work more for you

If you are mostly shooting 35mm-50mm range, then you could even try the Leica M system (but, as you know, no AF)

Lofty wrote in post #12735416
...Any opinions?

Don't get caught up in the fanboy-ism. Research both cameras as much as you can, try them out if possible, then go with whatever best suits your needs. You're in a good situation where you have no investment in either platform to worry about, so make the best of it. In the end, you just have to go with your gut feeling of whichever you feel most comfortable/confident with...otherwise you'll have that "could'a, would'a, should'a" feeling every time you pick up your camera.

I went to the dark side just recently and no regret. I had the 5D II + 7D and a few good lenses. Now I have Nikon D700 and a few good lenses. I like both focusing systems on the 7D and D700.

Nikon:
High ISO king
FF that can do 9 to 10fps
Pro AF system in a sub $3k body
Dual CF card slots on the D3 line
Better flash system
Lens lineup is getting better and better VERY quickly

Canon:
21MP FF sensor in a sub $3k body. High ISO still very good.
1080p video on a FF body
More granular lens lineup. (for instance all those f4 L lenses, non-L primes, etc.)

It's really a very tough choice. I know I had a difficult time switching to Nikon then back to Canon.

Why am I shooting Canon?

• 21MP and video on the 5D2.
  
• AF on the 1DMKIII which IMO is better than the AF on any Nikon body.
  
• Lenses, especially the 50L and 135L.
  
• Easier to change the ISO. Yeah...I know...but it's true!!!
  
• While I didn't find the ergos and menu system to be an issue while shooting Nikon, I think I like the Canon implementation better. Not a show stopper by any means though.

nicksan wrote in post #12745830
Why am I shooting Canon?

• AF on the 1DMKIII which IMO is better than the AF on any Nikon body.
  

Uhhh... Have you ever used the D3s? There's no comparison of the AF on the D3s to the 1D Mark 3. I own both and have one of the better focusing 1D Mark 3's and it still doesn't hold a candle to what the D3s can do. I love my Mk3 and it's a fantastic camera but when it comes to delivering at work, the D3s wins every time.

Don't go to Nikon. It's a Japanese product and I refuse to use one.

That's also why I drive a Honda instead of a Toyota.

hooookup wrote in post #12893365
Uhhh... Have you ever used the D3s? There's no comparison of the AF on the D3s to the 1D Mark 3. I own both and have one of the better focusing 1D Mark 3's and it still doesn't hold a candle to what the D3s can do. I love my Mk3 and it's a fantastic camera but when it comes to delivering at work, the D3s wins every time.

Uhhh...yeah.

Honestly, I don't hold any allegiance to either brand, and I try to be as fair as possible, but when I read things like "There's no comparison between the AF on the D3s and the 1D3" I just have to shake my head.

I suppose it depends on what you shoot. I shoot weddings and I can only base my opinion on that genre. I feel that the 1D3 focuses better in lower light. The D3s obviously is no slouch and does pretty much everything better than the 1D3 and is an AMAZING camera, however the AF in low light really didn't impress me all that much.

I'll say this though. The AF on the 1D4 didn't impress me all that much in low light either, so this is a VERY specific thing for me. In every other situation the 1D4 absolutely kicked ass and I prefer having cross type AF points spread out like that than have them just the center columns like the Nikon cameras.

I think when it comes to the pro level bodies, they are all going to get the job done though. The D3s is the high ISO king. There's no disputing that.