So that got me thinking who has the most practical costume?
The best I could come up with was The Question. Just a man in a suit. That's pretty easy to run around in, though maybe not the best for actual hand-to-hand combat. The hat might fall off, too, but no big deal.
Any Green Lantern can generate his or her costume from their ring, so that's carte blanche to have whatever kind of costume your heart desires. So Green Lantern costumes = practical.
Shapeshifters get a pass, too, considering that their clothes are a part of their body. (I think. No one's ever answered that question to my satisfaction.)
So, hooray for these guys.
Anyone want to add to the list?
Oh, here's a picture of Vril Dox. His outfit is pretty practical because it's a military uniform. And he's got jodphurs. I like jodphurs. And Vril Dox.