I like any test that I can do well at. The Typing Test: Free On-line Typing Test by TypingMaster, Inc. is a straightforward java app that lets you type one of 4 samples in 1,2, or 3 minutes to get a score (words per minute and accuracy). It is user-friendly in that it underlines the word you are currently up to and highlights misspelled words in red.

My score was a net speed of 79 words per minute and 92% accuracy.