I'm way overdue to write about how wonderful Valentine's Day was, but I hope you'll forgive me a brief technical diversion.
People concentrate on what graphics card one has in discussions of the SL client, and indeed it is an important thing... but there's something else that's important, as one can tell from checking on the processes running...
do-not-directly-run-secondlife, resident memory: 277.9 MB
(That's just after starting it; I've seen it in the 300s and pushing 400.)
So, yesterday I finally installed an extra stick of 512 MB of RAM, bringing me to a gigabyte... and it makes all the difference in the world.
Basically, you name it, and the SL client eats it: CPU cycles, disk space, graphics, and RAM. If your system is thrashing while the SL client is running, life is far worse. Make sure your system has enough RAM. Your Second Life will be much happier!