I don't know where you guys are getting your info from, but CrossfireX and hybrid Crossfire is way ahead of Nvidia's SLI ATM. CrossfireX can do four HD 3000 cards on AMD's 790FX chipset. And hybrid Crossfire can combine an the HD 3200 integrated GPU on a 680G board and a discrete graphics card (such as the HD 3650) for almost double the performance. It also often scales better then SLI a lot of the time.
I'd rather not invest in ATi products (personal bias, bad experience).
All I want is the most powerful upgrade I can possibly get for Aquos. Oh and are there any new Intel boards that support 16GB of DDR3? (i've seen some AMD boards that can handle 16GB but no Intels).
I don't think there are 4GB DIMMS yet, so, no. If you want the best of the best which you obviously do, get two 9800GX2s. But is it really worth the money? Are you not satisfied with your three 8800ULTRAs ?! But if you do decide to upgrade, you could give your old cards to me . I could find a good use for them.
You are part right. A GX2 Card is basically an SLI'ed card. It is virtually two cards in one. When you add two of those together, you get four processing cores, thus quad SLI.