My favorite is The End of the Eternity. It is a short time travel novel relatively stand alone, as compared to all of the other Foundation and Robots that all end up tied together. It might be a good place to test if you like his style or not before committing to the series. Or there are several short story anthologies out there. Or Nightfall.
I read a lot of Asimov as a kid and have always intended to go back and reread, but never do. My husband was just asking similar questions about him, as he liked the movie versions of I Robot and Bicentennial Man. Though they take plenty of liberties, that might give you an idea, too.