I believe I was using the latest available for what was either a 295 or 285

https://www.nvidia.com/Download/driverResults … spx/77225/en-us

I've pretty much always used 260.99. I started using that with my GTX260 and continued using it with other cards of the series, including my current GTX285.
I don't know if it's actually better than any other version though. I never observed an issue with that version but I'm not the best person to talk about a huge variety of games. I'm the type who mostly just plays the same few games all the time.
I tried a few slightly later versions but they weren't any different as far as I could tell.
According to my notes, 285.58 adds OpenGL 4.2 support for some cards, I don't know if that applies to the GTX285 + WinXP.

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One problem on these cards is that they are stuck permanently in their high power state if you have multiple monitors. I don't believe any driver ever addressed this, NVidia said it was intentional due to hardware limits.
If you only run a single monitor then this isn't an issue, it will switch modes properly in that case.

The 3rd party utility "NVidia Inspector" can be used to force the card into low power, but then you also have to set up rules for when it should switch the card back to high power. It's a little clunky but the difference in power/heat is significant with these cards.
I once forgot about that whole subject and was confused when a game ran at a crawl. Turned out the card wasn't switching to performance mode because I needed to add a rule to NVidia Inspector for that game.

If you want to monitor the temperature and have control over the fan vs temperature curve, Speedfan can do that.