it depends on what your definition of trance is.
if you're new.. you might like stuff from Ferry Corsten.
He's also known as System F, Moonman, Veracocha, Gouryella. Very commercial, very popular.
If you like that stuff, Dj Tiesto, Paul Van Dyke, and Paul Oakenfold might be to your taste.
If you like American trance, you could shoot for Christopher Lawrence, he's kind of in a class of his own.
If your into progressive (the good stuff, everything else is shite IMHO
), Sasha, John Digweed, Sander Kleinenberg, Deep Dish, are all great artists/Dj's. Alot of Global Underground stuff is groovy too.
Can't get really specific w/out details. Most are just Dj's that I've listed that have a track selection for you to choose from. From there you can get into artist specification, etc.