Who to get?

I'm getting bored of League, but I don't want to stop playing . I am looking for a new champion to pick up that would be really, really fun for me to play. I main support thresh, and support in general, but I generally find Assassins pretty fun, even if I'm kind of bad with them. I'm looking at and for an Assassin, but someone like seems really fun too. What Champion, not just one of these two, should I get?