Being a messy person myself I am practically a part of my mess. I like it and I wouldn't feel comfortable in a totally sterile place. But I don't live alone and therefore I have to respect the fact that others can have a slightly different opinion on the matter. So I do what I can to keep my mess from going farther than my room's doorstep. When I don't feel like doing my dishes I just leave them in my room so they don't offend anyone and besides I hate others cleaning up after me.

I think you should talk to your roommate about it and explain that she should limit her mess to the inside of her room and at least try to keep the shared area moderately clean. If she won't listen then I think you should consider finding a new apartment and a new roommate if it's possible. You definitely should not clean up her mess, she'll get used to it and will be taking advantage of you on a regular basis.

Good luck,

sparkling