GF1 DDR is better hands down.
Geforce2 MX os quite week. all the so called "DDR" MX cards have a 64bit mem bus, so they are essentially SDR. GeforceDDR is like 20% slower then GTS in decent resolutions (1024x768+)
Id say if yer buying a card, get nothing less then a GF2 GTS .. unless you can get a GF1 DDR for less then 50 bucks.