There are lots of good games out there. I'd tend to recommend Agricola and Power Grid also in the economic theme, but you'll do fine just browsing the recommendations at Board Game Geek and seeing what strikes your fancy.
http://boardgamegeek.com/
I own both of those games, and after play Agricola, I've decided that it's just too aggravating (too many tough tradeoff decisions) but Power Grid is a favorite, and in a lot of ways, if you are interested in playing Monopoly, you'll find Power Grid to be 100x more fun.
