I'm 22 and still live at home. But there are a number of factors that underpin this:
1. I study full-time at university (have been since I left school).
2. My parents are strict and Italian and won't even let me move out until I get married. xD (And hey, I'm fine with that.)
3. Because I study full-time, I can't have a full-time job. I definitely have time for a casual job, maybe weekends, but that wouldn't support me if I were to live on my own and study at the same time. And because I want to do well in uni - and because it's a pretty full-on degree - I feel that working more than 16 hours a week would jeopardise my study. So I currently don't work, although I have worked 16-24 hours a week in the past.
I do have to do some housework here and there but I have 3 other siblings and we all pitch in. Mum does the majority though (well she did until recently - she had surgery so we've taken over). The housework I do includes dishes, laundry, vacuuming, and general tidying up.
I can get home whenever I want. But I do have to call and give them an indication of my plans, an approximate time, and so on. It's the courteous thing to do.
I think you definitely have it a bit unfair. Have you brought it up with your parents before? You should point out that you're a good kid, and that you keep the house clean and you're doing the right thing by paying off your student loan and bills and such, so you should be allowed some freedom (post-10pm!). I was actually much like you, but once I started uni (when I was 18) my parents slacked off a lot more.
Also, are you the oldest sibling? I am. It often makes matters worse for us. xD