I simply enjoyed both growing up, though I tended to play Star Wars more when I was little. For Star Trek, I like the movies from Wrath of Khan up to Insurrection. In terms of the series, my favorites are The Next Generation and Enterprise. Deep Space 9 I liked for the first few seasons, but then I lost interest, and Voyager I was never able to get into. (I couldn't stand Kate Mulgrew, for starters.) The Original Series is okay, but I find myself unable to watch it very often.
I will say this, though: Star Wars EU totally tops Star Trek EU, which is so chaotically-inconsistent it's amazing anything ever gets done.