I actually read ALL 21 pages of this last night and at least there's only a few more replies to read today
Britney won the war. She hasn't been competing against Aguilera in years. When her name is along side the current crop of pop girls then that shows she's done a good job of staying relevant.
I may be one of the few here who remember when Britney debuted, when Christina debuted, and when, at that time, Mariah was in their position. This thread is forecasting the exact same things for Britney and Christina people were forecasting back then. The more things change the more they stay the same.
Britney knows what she does best and does it very well. She has found her niche, her audience, her sound, what she's good at and what she isn't good at. She does the things she excels at and stay away from things she doesn't. Sounds pretty smart if you ask me. There is no need to go outside of what she has proven to be very good at and successful at, so those wanting to her do some kind of polka rap album can keep dreaming. Ten years from now Britney will probably be pretty much where she is now.
Christina has not found her niche, can't keep an audience because she doesn't know what her sound is or have a signature of any sort(unless you count screaming out of tune), and seems to run away from the only skill she really has. Until she knows all the things Britney already knows about herself and the music she makes it's going to be another bumpy decade for Aguilera.
Sad Because we KNOW that Xtina has TALENT!!
I dont care about album sales, it s about albums for all times (Stripped, Dangerously In Love, Ray Of Light...), and I CANT imagine myself listening to some old Britney album 
