Fluttershy is my favorite, but I don't think I could really handle living with her. I'm going to college in the fall, so I put a bit of thought into this.
Twilight: She was originally my first choice, but I realized she'd probably hate me for making any noise while she was trying to study. Also, we're both "nerdy" and I think we'd be too similar.
Applejack: She actually would be a pretty good roommate. My second choice, probably. If I ever had a problem, I could talk to her and she would probably have the answers.
Rarity: I feel like she would be too stuck up and want everything to be neat and tidy. Also, she'd probably keep trying to make me wear pretty clothes, regardless of how unpractical it is to look pretty sometimes.
Rainbow: I think she'd be throwing her stuff all over and borrowing my stuff without asking and it would drive me crazy.
Pinkie Pie: Too many parties. Not gonna happen. I am not that kind of person. I like to be introverted and quiet and keep to myself.
Fluttershy: I don't think we would ever talk. I'm shy, she's shy. It would be awkward.
Trixie: No, just no.
Zecora: This is who I would want to room with. I think she would be interesting and fun to be around. I also think she would be really good at giving me life advice. She would offer a ton of cool culture into my life and I'm sure she'd share interesting recipes and things with me.
Derpy: She'd probably accidentally break everything I own or lose my favorite sweater. Not gonna happen.