Actually, in a gaming environment, the video card is going to be more important than RAM, but you're right -- the system's RAM, processor, and video card are the three biggest factors in regards to system performance. One note, though: you're better off with a faster timing scheme and lower clock speed on your RAM than you are with higher clock and sloppy timing. If you don't know what that means, just get as much of the fastest RAM your system will support, plug it in, then smile and nod.
As for the 9700 Pro and the like, though, a processor really isn't going to bottleneck it *that* badly. Features like anisotropic filtering and anti-aliasing can make jaw-dropping improvements in the appearance of a game, and while they heavily tax a GPU, they don't place any additional strain on a processor. Very few moderns games need a real beefy processor, because modern video cards are essentially a seperate subsystem that handles ALL of the graphics and rendering. Yeah, if you have an older card or game that uses software T&L or something to that effect, your graphic quality will be very limited by your processing power, but it's not like you should get a crappy video card just 'cause your processor's a little out of date.