I have both and on the 5D MkII I like the way ISO (set to automatic) will rise if the light level falls. Good for those f/5.6 telephotos.
It also has the feature where highlights and lowlights can be evened out. I found it subtle but I need to explore that further.
I seldom use the movie feature and didn't get it for that.
If you don't want the large file size, select a smaller image or more compression.
It also has the cleaning feature whereas the old 5D doesn't. I read the old 5D is notorious for dust but I've been careful and I don't think I've had too many dust issues. (haven't checked recently, nothing obvious)
The old 5D has the Digic3 and the MkII has the Digic4. I think the 7D has two Digic4 processors. I haven't noticed anything between the two except the Mk II has face recognition etc.
Daryl.