Depends on how much you paid for it. I would have gone the ATI 9700 video card but what you got sounds good, too. I am running a Pentium 4 2.8 GHZ (overclocked to 3.15) and I also upgraded from an AMD 1800. Like you said, it really flies compared to what we had before.
Edit: The first thing I would do is upgrade to more memory. I am running 1.5 GB DDR-333 and it really helps if you have a lot of stuff open all the time.