Your Celly 1.3ghz is going to hold back any o fhtese DX8 cards so a CPU upgrade might be wroth saving up for over the coming months. Int he meantime while your CPU is underpowered simply enable 'eye candy' to soak up some of the gfx card power your CPU can't tap. On the Rads I'll mention you want 16tap AF, maybe even try 2xAA if the res is maxed out in the game. On the GF3/4TI you'll want 2xAA & 4xAF. Anyway, on to the cards...
GF3 are decent enough for 3D gaming but compared to all the Radeons and the GF4TI they are let down in image quality, dual display ,TVout and DVD playback. Rad9000PRO, Rad8500LE, Rad8500 or Rad9100 (in rough order of speed form slower to faster, 10-20% between each) are great all round cards, only let down by AA and poorer CPU scaling (they don't get the most out of the faster CPUs). The GF4TI4200 offer great perf and are now pretty cheap, they're faster than the Rads I mentioned previously BUT diffs are only there on faster CPUs, if you want to play with some AA & AF and upgrade to a XP2000+ / P4 2ghz this is a good choice. All these cards are very good so see what prices are like. 128MB is worth the little extra it costs, do check the clock speeds of the 8500 series as they tend to vary a lot (230/166 - 275/275), and 4200 brands to avoid are Evga, Aopen and Gainward.
If you don't have plans to upgrade your CPU simply get whatever is cheapest as the diffs between GF4TI4200, Rad9000PRO (only consider the PRO), Rad8500 (inc LE) and Rad9100 are very small, if non-gaming aspects aren't a worry you may find a bargain GF3 card.