Tunstall used to be a lot more interesting before the ol' record label figured she'd be better off doing dido-esque lovey pop. I still have a big soft spot for Black Horse and the Cherry Tree. Plus, I like it when KT pushes her voice, has a nice clear break up, reminds me of an overdriven fender tube amp or something
Winehouse... I dunno, Every time I've heard her live on the telly or stuff, she's reminded me of the old Vic Reeves "club singer" slot that used to be on Shooting Stars, a kinda slurring mess really.
(Go here, and skip to about 5:55 for a prime example...