I love Tristana. Everything about her rocks. The looks, the cannon, the personality (happy and tough with a touch of crazy bloodlust). On top of that her mechanics feel so good! Whole kit gels together real well. Best base range in game, goomba stomps, heal reduction, best AS steroid (great for killing towers when combined with her insane range), a nuke that also let's me knock away people who get in my face.
What's not to like?
Edit: I'm not trying to sound hostile, but there are a few giant problems Tristana faces that make her harder to pick up than other carries