I dont know about De Niro, his older stuff was absolutely fantastic, amazingly good. Taxi driver is one of the best films of all time, hands down. BUT, lately De Niro seems to play more of a charactature of himself than anything else, its pretty sad really. I honestly couldn't say what the last good movie he has done was..... The last really good film, Heat? 1995?
Getting a little off topic here, but what do Taxi Driver, Raging Bull, Casino, and Goodfellas all have in common? Martin Scorsese, arguably the biggest reason for De Niro's fame, considering he's directed virtually all of the *Great* movies De Niro has been in. I would be damn excited if it was staring De Niro, and directed by Scorsese, considering he has actually made a few films worth watching since 1995. Bringing out the dead(good), Gangs of New York(amazingly good), The Aviator(alright), The Departed(amazinly good).