many strong players did play gambits, I doubt many class players could handle morphy's evans for example.
Their are not many lines in the naj that have black sacrificing as at least to me seems to not be in the spirit of the opening. White does have many good sac's against the sicilian however.
nothing in chess is worth learning persay but you do need to know how to face gambits and may as well play them yourself at your level, look at the kings gambit, danish gambit, and evans gambit.
I'm looking for some more aggressive openings especially for blitz games, which I lose on time more often than I'd like to. Would it be worth it to gain a fairly deep understanding of some gambits? If so, which ones?
Albin and Benko I've heard of and seem legitimate, though I don't know much about them. I also play a lot of Sicilian (always Najdorf variation)--are there any gambits within the Sicilian worth learning?