I have a Dell PC, running openSUSE10.3, with a Intel P4 clocked at 1.8 GHz and 768 MB of RDRAM. The PC will run the applications, but it is still slow. I think a lot of it comes down to system BUS speed. My PC is 6+ years old and I find it lags on many features I want to use with openSUSE.
I think a PC running a P4 2.5 GHZ with 1 GB of RAM on with a 800 MHz FSB and hard drives spinning at 7200 RPM would be a good fit.
Maybe I can tweak openSUSE 10.3 to run faster, but you can only get so much from a PC before you shove it onto the highway at 75 mph to ease your stress. 