GPS

I use a Garmin eTrex Legend (that's the little blue one).  Plenty of GPS receivers have come out since I bought mine a few years ago, but it's been such a great little unit for what I use it for that I've never felt the need to upgrade.

One feature that I love about it has nothing to do with the inner workings.  It has rubber around the outside, which makes it easy to hold  onto, even in rain or with sweaty hands. 

I primarily use my GPS receiver for geocaching, and because of that, I'm a firm believer that these little tools should be WAAS enabled.  WAAS stands for Wide Area Augmentation System, and it lets you pinpoint your target with much greater accuracy than a unit without WAAS. 

I also love the "click stick" on this and many other Garmin models.  It's like a little joystick and makes it very easy to navigate between pages and to move around within pages.  It's very easy to enter waypoints, for example, because I can use the click stick to maneuver around the screen to enter my text and numbers.