
For 3D the TI200 should hit TI500 speeds while the 8500LE should hit 8500 speeds. 8500 cards tend to give almost identical perf to TI500 so in 3D it will be very tight. When it comes to AA the GF3 cards are HUGELY better, as for Aniso it evens out, 8500 can do it at half the hit but at lower quality, however upping the Aniso means you get about the same speed and quality, it is very close for Aniso.

When to comes to image quality, dual display, TVout and DVD playback the 8500 is light years ahead although Gainward and Leadtek GF3 cards did have decent image quality. When shopping for an 8500 do check the clock speeds as these vary by manu and oem/bulk vs retail, also dual display often varies between manus so double check that too if it's important. 128MB gives the 8500 cards a very nice boost even before the extra RAM is needed, when the extra RAM is needed there is no substitute for having enough and 128MB will serve you better in the long term for certain, plus you'll sell a 128MB card much easier and for more cash when the time comes.

You could consider a GF4TI4200. It is obviously faster than GF3TI500 or Rad8500 esp when it o/c's top 4400 levels. It has even better AA than GF3 and incorporates much better image quality, dual display, TVout/VIVO and really pulls way ahead withthe faster CPUs which is great for the long term.

You have 3 great choices and you won't regret any of them.
1. Staying with your GF3 as it still rocks.
2. Selling up and shifting to Rad8500/LE to gain IQ and some other nifty features.
3. Selling up and shelling out a little more cash to gain IQ, some other nifty features, increase perf and esp reap benefits with the faster CPUs.