Garmin Forerunner 305 (less money, splash resistant but not good for swimming, 10 hrs battery time)
Garmin Forerunner 310 (much more money, fully waterproof, 20 hrs battery time, a little smaller and lighter but still clunky)
I started with the 305 and that's what 'Bent still uses, as well as many other people. Functionality-wise, it should do the trick. I moved up to the 310 with birthday money from my parents last year, mostly because I thought I might use more than 10 hrs of battery time on some of my longer training / racing trips. If you're OK with the cost, I'd get a 310 but the 305 is also a very good watch. It took me quite awhile to decide to move up and without the birthday money as an excuse, I probably wouldn't have!
Thanks Bash. My birthday's not until October. :) .