The first thing you need to do is uninstall Game Booster; and never again be deceived by "optimization software". You have a quad core and 8GB's of RAM, which is more than adequate. Game Booster isn't doing anything for you, in fact, it may be doing just the opposite.
The next thing you need to do is rid yourself of the notion that, "having a few programs open", despite your cpu and RAM, won't affect performance. It all depends on what programs are open, and what you're asking them to do. Again, if you could stop being stingy with information and just tell us what you have open, this would go a lot easier.
Your RAM is nice and tight, which is perfect for your chipset. However, you are running 2T. A command rate of 1T will make the system much snappier. However, before you adjust this setting, make sure you know how to clear CMOS just in case the board or your RAM doesn't like running at 1T.
Fourth, I would suggest reading two guides: sygnus' gaming guide, linked in his signature, and the Windows 7 Optimization guide in the Tutorials section:
http://www.sevenforums.com/tutorials/11728-optimize-windows-7-a.html?filter[2]=Performance%20Maintenance
100 fps is meaningless. Your monitor can only display 60. I realize the more fps the better the experience, for a variety of reasons, but instead of focusing on maximum fps, which is again meaningless, instead focus on minimum fps, which is what really makes or breaks the gaming experience. When everything is flying along at 80 fps things are great, it's when fps dips down to the 30's that things begin to suck.
Nobody can say with any certainty what the requirements of Black Ops will be; however, if history is a good indicator, and it usually is, then pretty much any decent modern mid-range to high end card will do. Again, the question is whether you want DX11 or not? There are a lot of good cards out. Pick one. Come back after you've read some reviews and I'm sure there will be no shortage of opinions for you to choose from.
So, to end up, stop running applications when you're gaming; optimize your rig with the guides provided; get a decent graphics card.