Which nVidia driver for Vista 64?

Oops, I forgot to answer Bailey's question. Yes, I have tried the most recent drivers; I've had more success with earlier drivers.

I'm really hoping the texture-memory slider was the issue for me. So far so good, but I'll report back after another day or so. The acid test is: can I stay online at a busy club for an hour?

And I realize I also forgot to answer Chosen's question about people who say they've had trouble with Driver Cleaner. I've been slacking in monitoring my own thread!

Anyway, Chosen, you may be right that my friends' trouble with Driver Cleaner was not the program's fault; neither one is a sophisticated user, and for all I know their troubles are completely unrelated. (Your story about people claiming that DC 'downgraded' their PC sounds familiar.) I'll try to learn more from them. Also, in my own case, I have XP set up on a separate partition, so it's not like I'm risking much if I try Driver Cleaner. For now, I'm hoping the texture-memory thing has solved my problem. *fingers crossed*

Brief update: I've had somewhat more success with my texture-memory slider dialed down to 386Mb, but it's hard to be completely sure, because this week I've been running multiple instances of SL to test stuff with an alt -- and I've had two or three hard crashes while doing that. I haven't had any crashes at all when running a single instance of SL. Also, for the first time, I have been able to play in full-screen mode, which I gather is easier on my video card. One question is: if I run multiple instances, should I run them all full-screen?

Anyway, once I get through this phase of testing, I'll return to running one instance of the game, and I'll have more relevant feedback to report.