See LiL, I disagree, and I swear that it's not just because she's hot (I actually have always preferred Claire)!!!

I think that she has issues, but in Season 5 when she decided to come back to the Island to save Claire, that's when she started to redeem herself and act unselfishly for the first time.
Yes, she is annoying because she wavers and is selfish and runs, but what I like about that character is that I believe it is a very human trait to be selfish and run from things and be afraid to face them and deal with them -- that's why, honestly, I can relate to her. I think women tend to be more frustrated by her because they see her as being a weak character and only there as a sex symbol and get frustrated by her going between Jack and Sawyer, and I totally get that from a feminist perspective.
I feel the same way about Jack - I know a lot of folks are driven crazy about him because of all his flaws, but I feel like that's what makes him relate-able - his stubbornness and inability to let go are such annoying character traits, but they are very real and are meant to make us step back and see it that way.