We have been hearing a lot of reports that Revit 2010 is not very stable. Many users have been experiencing crashes in the product. Through some investigation of Customer Error Reports (CER), see a great post about CER here, we are seeing that many users are crashing due to out of date video graphic card drivers.
In Revit 2010, there were changes made behind the scenes regarding the display of graphics in the application, a good post of the subject can be found in a post on Inside the Factory called Tuning the Graphics Engine, these changes might cause your old graphics card driver not to work as well before and may be the cause of the instablilty you are seeing.
Please, make sure that you are using the latest version of the driver for your graphics card.
This will greatly help the stability of Revit, preventing crashes from occuring. Also, if you are crashing, make sure you submit those CER reports with your email address and then go ahead and contact Autodesk Support or your Reseller for help.