- Note that this post crossed zanthor's post in the ether, so ignore any duplication of information -

> if using 2 1gb
That'll be 1Gb flat then, leaving you with a shade over 2Gb of available memory under a 32bit OS.

It doesn't matter if you actively use them, they're still "mapped" into memory unless you've physically removed them. Disabling one in device manager might have the same effect, but I couldn't swear to that.

- Without SLI wouldnt it still provide more FPS with twice the cards and ram?
Generally not. Applications need to be specifically coded to take advantage of SLI / Crossfire technology. You might get a gain if you connected a monitor to each (i.e. drive each monitor from a separate card), but I've no experience with that myself.
Was told that 64 vs 32 wouldn't make any difference
Ohhh no you weren't! Silencer specifically mentioned the increased memory addressing capabilities of 64 bit OSes in your thread about the machine before you ordered it

32 bit OSes can only address an absolute maximum combined total of 4Gb (including video RAM). It's actually a bit less, but that's a good starting point for this sort of discussion.

-Do add-ons effect this?
Add-ons will increase the total amount of memory each WoW needs, but it's usually a small amount in the big scheme of things. Some add-ons can also cause frame rate reductions if they're hooked into lots of events and/or aren't coded very well.

It'll be interesting to see how much memory the task manager reports, but I think I see an (pain-free) migration to Vista64 in your future