Marvel Girl/Phoenix/Rachel Grey Summers has been a favorite of mine since the classic Excalibur days - I don't think I've drawn her since I was about 13 years old though. She's kicking all kinds of ass in Wolverine & the X-Men, too. Hope you dig it!
Rachel Summers is the daughter of Cyclops and Jean Grey from an alternate future timeline, a pretty dark one at that. She's a pretty cool character with a great history - check out old issues of Claremont and Alan Davis' Excalibur, they're worth the read.