As far as I know, from what I was told some time ago, the FBI does not have a good way to recover certain filesystems after they have been deleted, such as ReiserFS.

I'm not a fan of math, so I owe a lot to my calculator for getting me through tough problems. The TI-89 is fast (can be overclocked) can do algebra, 3d graphs, and anything else you might throw at it. It is leagues ahead of the 83. I'm in college now, and the 83 is still the standard in most classes though they'll let you use anything. This calc is also allowed on the SATs and APs, at least they were when I took them 4 years ago.