I've been looking into vid cards. This is what I gathered from reviews (I'm only considering NVidia GeForce products).
First of all, don't spend money on any GF2 MX card if that's what you have currently. An addition of 32MB will do very little difference. A couple of reviews I read said that if you intend to play at a resolution of 1024x768 or less (the typical resolution for 17" monitors), the 32MB models are sufficient, because there is very little gain in performance. (It's more the speed of the memory that matters, and that depends on the manufacturer. That advice also goes for the GF2 GTS, available in 32MB and 64MB models.)
The MX, MX200 and MX400 are all in the same family, but the MX200 is a fraud. Its specs are half of the MX and the MX400 in terms of memory bandwith, hence hugely reduced performance. The MX and MX400 are similar in specs.
If money is an object, I'd go for the next series of GeForce in terms of performance: the GeForce2 GTS, GeForce2 Pro or the new GeForce2 Titanium (in order of performance). They're all in the same family, but I suppose the Ti200 will replace the GTS and Pro on the shelves. (I found very few Pro models in local stores, mostly they're GTS and a few Ti200s.)
If money is not quite an object, then buy a GeForce3 Titanium 200, or a regular, classic GeForce3. According to reviewers, the Titanium 500 is too expensive for the added amount of performance over the Ti200.
I you have more money that you know what to do with, then by all means, go with the Ti500.
A note: a reviewer said that if you have a 17" inches monitor, then you probably won't play at more than 1024x768, and in that case it isn't worth it to buy more than a GF2 (GTS, Pro or Ti200). A GF3 is worth it only if you have a bigger monitor and intend to play at higher resolutions, according to that reviewer.
Note also that the choice of the card is important. Some makers compromise on the NVidia official specs and their cards don't perform as good (mainly because they put memory with a lower bandwith). Some makers don't, and actually improve on the specs. Asus cards seem to be good candidates, but there are others as well.
[ 11-27-2001: Message edited by: DrSoya ]