CED M2 for me. There's a thread here that discusses it and others.
I particularly like the fact that it's brains aren't anywhere near the sensors, and that you just need a simple USB cable (which it comes with) to download your shot data to your computer.
"You need only reflect that one of the best ways to get yourself a reputation as a dangerous citizen these days is to go about repeating the very phrases which our founding fathers used in the struggle for independence."
- Charles Austin Beard