Do your own research and you'll find that the AMD dual core overall performs better than anything Intel can put on the table (including the Intel dual core) except for the very high-end Preslers(955/965). If you want to spend less than $400 get the X2 4200+, if you can spend $900 get the FX60.

And don't bother with a pc raid setup. They are not worth the hassle for a typical pc such as yours since the performance increase in negligible.