I have the ciclosport M434 (I think that's the model) that shows current elevation, total ascent, total descent, max elevation, current % grade, avg % grade up, avg % grade down. Also all the other normal cycle computer stuff, of course.
it doesn't have a file download, there's a more expensive one that does have file downloads, but you have to buy another extra interface, and it's quite spendy.
The nice thing about it is that since it's a cycle computer, the battery lasts forever, as opposed to those garmins, that have to be charged daily. doesn't matter if you are in town, but on tour there's no way I would be a slave to a daily charge.
Also, if you go the GPS route, make sure it has a barometric altimeter, the GPS based altitude readings are extremely unreliable.