I'd go with either 7.78, 14.10, or 21.81. Nothing later than that.
I think those are the most stable WHQL drivers.
I'm not sure the 21.81's are actually WHQL... but I know folks have had good luck with them. Try the 7.78 's first, and then the move on to the 14.10's and the 21.81's if you don't have good luck with those.
http://www.guru3d.com/files/When in doubt, stick to the WHQL drivers. Also for older model cards, stick with much older drivers. Most times the TnT2/GeF1 level cards work very well with the 7.78's and that's what I would recommend. Also look around on guru3d and find detonator destroyer so you can wipe out all traces of the older detonators before you switch versions.