Things have improved since 2005. I just bought one of these and used it last week at a track day. Very happy with it!

http://www.performancebox.co.uk/

Excellent timing and data logging modes. Plenty of support.

 

found a great mount for a Bluetooth GPS receiver. triple suction on the windshield, or huge single suction on the windshield. just thought i would share...

 

I use the Ultra-lap timer. It lets you enter several track names, set the lap times for each track, and stores all the laps for future download to your computer. (date, time, ambient temp, laptime, etc..) Whatever you get I'd recommend insuring you can download to your computer. I then pull the information into excel and graph up my lap times to see how consistent I was and how I compare with the last time I was at the track.