my mom has a Garmin talking GPSr in her car, and loves it.
I have a Garmin eTrex Yellow, as low tech as a GPSr can get, just for geocaching. I'm very happy with it.
The Geocaching forums are always full of Garmin vs Magellan debates. (Kinda like Campy vs Shimano)
Both are good reliable brands. Pick whichever appeals to you most and you probably won't go wrong.
(my mom's has an Emma Thompson like voice option. very soothing.)
"If Americans want to live the American Dream, they should go to Denmark." - Richard Wilkinson