I'm finding this on the main client and the first look client, both.
What once was (I think) a weird freeze-up of the client now and then has been a crash requiring full reboot anywhere from 1 to 30 minutes of being online; 5 minutes being typical. I suspect graphics card issues.
First instances were on my P4 / Radeon 9800 work machine, then with the latest update similar problems with a (I'm not home - forgot the stats) - a fairly modern dualcore and a geforce 7800 I think. Both about 2Gb of memory; using DVI to Dell widescreens, Windows XP; nothing else that important I can think of.
I *have* been able to get an ancient 1.5 GHz P4 with a Geforce2 MX200 to run in a stable manner. But for my in-world business that's about like trying to run a road rally in a motorised lawnmower.
I'd upgrade to fix this problem if I could, but... how?