#1 - Melinda Doolittle
The prevailing thought would be to put Melinda in the two spot behind Lakisha Jones, but I think that is merely the benefit of Lakisha's one great performance (of the Jennifer Hudson song). Melinda is a better singer. She may not have the best voice in the competition (it's still incredible), but she is a professional singer who has improved (and will likely continue to improve) her stage presence. It's still relatively early, and you don't want to peak too soon, and I think Melinda still has a lot of room to grow.
#2 - Lakisha Jones
Lakisha is great singer who has a huge voice. Absolutely humongous voice, which is, for now, going to make her seem like the best singer out there. Unlike Melinda Doolittle, I think Lakisha may have hit her pinnacle a little too early in the American Idol competition. I don't know if she can put on a better performance that the one she did on the Top 12 female show, when she did the Jennifer Hudson song. It might all be downhill from there. She'll still be good, mind you, but when you set the bar that high on the first show, you risk the perception of disappointment from then on out.
#3 - Jordin Sparks
Jordin, at 17 years old, is doing incredibly well. Her voice is stunningly mature for her age and, of the rest of the females, she may be the only one who can go toe-to-toe with Lakisha or Melinda. However, judging by last week's performance, Jordin can be wildly inconsistent. She wasn't all that good last week, and that can be a frustrating to the viewer, because we can see the potential. It's so obviously there that we expect a great performance every time from Jordin. But that's just not going to happen.
#4 - Chris Richardson
Not my favorite, but out of the guys, he probably has the best chance at winning. Chris looks and sings like current male pop stars (e.g. JT), but I don't know if his voice is that good. Yet. He's been improving. However, what he does have going for him, besides the aforementioned pop star looks, are his expertly polished performance skills. He is comfortable and confident on stage. Don't underestimate what that can do to the voting audience. They'll eat it up. Look for Chris to, at the very least, make the Top 6.