As far as versions go, i'd say that this would depend on what kind of user you are. If you want the least possible involvement with firmware and map updates, but want the latest of both, you'd be better off with an LED unit (version e/f/g) that has newer hardware and usually the latest firmware/maps. Otherwise you could get an older version (a, b or c/d) for less and do the updates at your own risk. Some sellers can also ship the older units with updated firmware/maps that way you can save the risk of bricking your new unit. The latter versions also have 40gb instead of 30gb hdds, but the free space available for music remains about the same ~20gb since the rest are taken by maps and POIs.
