The MX420 by MILES! The 7000 is = to a TNT2 Pro in benchmarks & such.
Having said that: the GF2 MX400 is only a little behind the GF4 MX420 & is also better than the 7000. The only *plus* the 7000 has is DDR & it still can't keep up w/the MX's.
I can tell you're 'stuck' w/a PCI card (that's what the 7000 & MX420 are) & I'm in the same boat. Get a GF & not the 7000. I did & since I've seen comparisons: I'm glad I didn't get the 7000! :grinthumb
I've spoken to PNY & was told that when the 'new' nVidia chips come out: there will be a hi-performance PCI card in the release. I got a GF2 MX400 in the meantime.
HTH,