You absolutely can't go wrong with an nVidia graphics card. Here's a pretty good one for $29 that'll give you more than acceptable performance:
http://www.tigerdirect.com/applicati...570&CatId=1087
Alternatively, newer ATI hardware with recent drivers is also a strong alternative.
If you would like, you may send your world to
support@worldviz.com and we'll test it with nVidia hardware and ensure that this resolves your crashing problem. BTW, what kind of crash do you experience?