Before my Garmin, I was very happy with this one from PlanetBike.
http://ecom1.planetbike.com/8003.html
Wireless, but the best feature is to turn the unit on/off/reset you push on the whole body "upwards" - works great and no finicky little buttons to remember. I think I paid $30 for a new one on on eBay...Highly Recommended!