I like to think I can play many personality types pretty well. I try to sample every kind so that I can get better at each one. Being the same kind of person for every roleplay is just... So boring. Plus, I enjoy being challenged.
Ultimately, my best might be 2 different ones. I'm good at playing badass shameless evil jerkwads because they are my favorite. However, I'm also good at playing sensitive nerdy pothead losers because that's what I am in real life. x3 It doesn't matter if it's male or female for these two character types, but I am way better at playing dudes than chicks. As well, I just like to play flawed people. Nothing is more flawed to me than a misunderstood geek, or a villain. Heh. Not saying ALL of us are 'flawed' when I mention geeks, by the way. >>; It's just that... In the eyes of those who are 'normal', you know... *trails off and kicks a rock*
Anyhoo.
The sorts I need more practice on are like... Vulnerable girly girls with bubbly attitudes. I thoroughly enjoy playing fashionistas and the like because they're so different from, well, me. I don't always do a good job, though. It's only this kind I have a hard time with, because I can play feminine males with the same interests just fine. x__X I think it's because I don't get many opportunities to try out girly girls... People are always wanting men from me, or women who can throw a punch and break a nail if they need to.