I would suggest that SLi isn't the way to go with the video card market looking the way it currently does.
Rather than start a thread in each subforum, you would probably be best served by a thread in General Hardware, which is where advice on new systems is handled all at once. If other people don't have to track multiple threads on your build you'll get more input. Running from thread to thread to give advice on a system tends to make otherwise helpful people give up.
There are also several useful stickies in General Hardware. One is a list of recommended gaming parts maintained by modoheo, and another is a list of questions that you're going to get asked anyway, so you may as well answer them up front. If you do, you'll find the quality of responses in your thread greatly improved.