I've been caching with a Nuvi 500 since around January of this year, and found close on 300 caches with it.. It is a great GPS, ideal for caching with custom Geocaching Functions... It is very user friendly, and it does not take too long to get the hang of it...
There is lots of plusses, but the only drawback is that the battery life is not too hot... They claim up to 8 hours, but my experience puts the best performance at about 3 to 4 hours... Doing urban caches, this should not be a worry, but hikingtrails, forrests and mountains will frustrate you...
Take a look at http://www.gpsmagazine.com/2008/07/garmin_..._500_review.php