I have the Garmin Emap. Here's one for sale on Ebay if you want to see the size of it (http://cgi.ebay.com/ws/eBayISAPI.dll...category=34289)

I used it yesterday on the bike. When my wife and I ride I've found our distances are often different when we finish so I took the GPS with me while we rode and compared our computer distance to the GPS distance. Turns out her's is a bit more dialed in than mine.

I have used my GPS for all sorts of stuff. I have mapping software running on my laptop and have used it to plot my trips - this is really handy to have if the Interstate is blocked due to an accident. I can easily find an alternate route.

About the only drawback of the eMap is that the map included with the device can not be updated. You can store additioinal map details on a separate memory card but the base map can't be updated

Zack