I have the Garmin Oregon 450...it's awesome.
Touch screen (that works with gloves on) so you don't have to fiddle with buttons while riding, for instance setting a waypoint while riding
Barometric Altimeter for correct elevation readings
Waterproof, I use it kayaking
Very durable, I have crashed hard with this and no issues.
AA batteries instead of proprietary rechargeables, necessary for long trips in my opinion
Supports ANT, heart rate monitors, and garmin biking accessories, I don't use them so can't comment on usefulness.
There's a $50 rebate available right now on it as well...
oh and the handlebar mount for the oregon line is really easy to use and solid
here it is mounted on my 29er for mountain biking to give you a sense of size