Help with a new screen name?

I'm going to be a freshman next year and want to change my screen name. I want it to be more sophisticated rather than kiddish and fun. My current sn is something like xilovepearlrainx. I really have no idea why I made that...I made it in 5th grade though. I want my new one to maybe include my name (Kate/Katie) or last name (Mahoney). If it helps, I play tennis, I golf, and water-ski. I'm not sure I want it to have anything to do with sports though. I'd like something sophisticated but cute at the same time. My favorite number is 2...umm.. yeah. Thx =)