I have Garmin 2610's on my Speedmaster and Tiger. There were some good deals on refurb units a few months ago.
Check out advrider.com "laying down tracks" forum for all the info you could ask for.
http://www.advrider.com/forums/forumdisplay.php?s=ccc9cfdf2cc03cb4452ee6a0b30c1585&f=37
