He's one of the best actors ever imo. Watch Taxi Driver, Raging Bull, Casino, Godfather 2, King of Comedy, Goodfellas, Mean Streets, The Deer Hunter, Cape Fear (remake).
The classics that made him a legend.
I thought he was on his way to making his mark as a director, started off with a bang w/ A Bronx Tale but sort of stopped for some reason. Looks like he's getting back into it though, sure he consults with Scorsese so we'll see how that turns out.
I was pleased with Taxi Driver as a whole. I like Robert DeNiro as an actor as well. His first on-screen appearance post-haircut is as close to an iconic cinematic image as I've seen. It made me want to get a haircut like his so I could be cool like him. I didn't get that haircut though, because I knew he'd always be cooler than me no matter what. I think he shot a guys' hand off, not that that's cool but, I digress.
Anyway, I have not seen Mean Streets, Deer Hunter, or The Untouchables. I will have to see if I can find them at my local library.