If you are crashing when right clicking on people to view profiles, or send an IM, it appears to be related to the new resizable UI interface.
Do this: Go to the Edit menu on the top bar of SL, and pick Preferences, go to the Graphics page, and clear the check mark from the box that says Use Resolution Independent Scale.
It worked for me, maybe it'll work for you all too.
Edit: Grid goes down just after I posted this, this is probably useless information now