I own a 2009 Streetglide and needed a GPS since my wife tells me I'm the most lost person she knows. So, after much research, I bought a Garmin 2820 off of eBay (BRAND NEW, NO shipping, NO tax for $239). I received it in about 3-5 business days.
I tried it in my car first since the mounts were not shipped yet (got my RAM mounts from The Mount Guys and their customer service was top notch, and their prices were competitive as well).
The Garmin is bluetooth capable in case you have a helmet set. If you do, you can make calls via your GPS once it's paired with your phone, or you can get verbal turn by turn directions.
Some people would rather spend around $800-900 for a Nuvo, but why bother? Go with the Garmin and buy some slip ons with the cash you save. The thing I like about it is the large screen. A buddy of mine bought Harley's GPS and the screen is puny. I'd rather be able to see a larger screen so I don't have to take my eyes off the road for very long. I could not be happier with this product. Couple it with the RAM mount that has the wiring for a motorcycle and you are good to go.
If you are interested in getting one, the guy I went through can be reached at:
newitemsonly@hotmail.com