What kind of a bennifits do you get if you go the x16 path?
also, what exactly is the difference (pros/cons) in going w/ SLi over Crossfire?
Not exactly sure on this one. It all depends on the total bandwidth of the card. It was my understanding that an 8x vs 16x isnt a different on today's cards.
I run a crossfire rig with 1900's, my motherboard only supports 8x - 8x mode. Newer ones support 16x - 16x.
I get fairly good performance. I would suggest trying 1 card first to see if this suits you. I game at 1600x1200 and like my AA and AF, so crossfire is good for me. If you are not a high res gamer and game at 1280 or 1024, I would suggest trying one out before buying a second.
Right now two 7900GTXs in SLi is the best dual slot setup hands down, there is no real performance gain of 16x vs 8x although newer dx10 cards could change that...crossfire is good and getting better but SLi puts more power to the ground...i say this because a signgle ATi X1900XTX will beat a single 7900GTX, but two 7900GTXs will beat two X1900XTX , all of this is irrelevant if you game under 1600x1200 or 1920x1200 for that matter, that is where dual gfx card setups really kick in, unless your playing Oblivion