Mistborn by Brandon Sanderson is some of the best fantasy I've read in a long time, with a very innovative magic system that ties into the rest of the world and the story like cogs in a swiss watch. It's also the first of a brilliant trilogy.
Jhereg by Steven Brust, also fantasy, is the first in a long series of novels about an assassin. Brilliantly told from a very compelling viewpoint (and there's now eleven books in the series, so if you like it, it'll keep you reading for a long time).
And if maybe you prefer sci-fi, I can only recommend Old Man's War by John Scalzi, which is the first in a series that now spans (I think) five books.
Those are the best series that I've discovered over the last couple of years.