Help me pick an iPhone case!

Look what my parents got me for my belated birthaduation!

(I call this my just got home from eight hours of work at the daycare and now lying on the couch and taking terrible photo booth pictures of myself look. How's it working for me?)

Yeaaaah! I feel like such a creative type when I'm carrying it around.

I need your help, though! I have to buy a case, and I don't know which kind to get. Any recommendations (or non-recommendations)?

Here are some cute ones I've seen, but I'm not limited to these (or to pink). I'm hoping to find one that is both safe and functional and not too expensive.

Thoughts?