I recently bought a new garmin gps and have been extremely pleased with it. There is a whole set of free software you can download that is extremely useful. Go download Garmin Roadtrip and check it out.
Garmin has also done a stunning job of open-sourcing their gps data files, they're all standard, fully-documented and compliant xml files. The only complaint I have is that they still make pushing information TO the gps difficult. It's very easy to read absolutely everything on the gps to the computer, but the files the computer has access to are copies of the data files on the gps, which are hidden and cannot be modified except by garmin's software. BUT, you can download them using their app, modify the xml to your heart's content, and then use their tool to reupload them to the gps. Also check out MacGPS Pro and RouteBuddy.
You will need to download the Garmin Communicator plugin for your mac. Tight browser integration (firefox OR safari !) to the point that it's almost scary how it works. But all the candy makes me really wish it were somehow integrated in with Google Maps. That would be heaven.
