How important is it to you to have a color display? Thoughts on brand preferences? Ease and cost of map software? Good or bad experiences with particular models?
I still have my first GPS, a Magellan, and it does not have a color display. I see the color as a convenience but it is not crucial to a GPS. Garmin is also another brand I have used bu do not own. As long as you stick to a name brand such as Garmin or Magellan you really cant go wrong. I`d write down the features you want and then search for models that fulfill the list with the most reasonable cost. If your list has only 3 things on it then there is no need to get one with all the bells and whistles if you will never use them.
Any decent mapping software will be compatible with most of the major brands. Such as a Nat`l Geo Topo program.
One thing you may want to look for is expandable memory, so you can add an SD card for larger maps. Its hard to give you a particular model if we don't know your needs.