Popular Female Singers in the past 2 decades

All of the above, plus Natalie Merchant. My wife just bought Adele's "21" album. It's very pop sounding, but not bad.

Erikminer, Joni of course. Her albums featuring Jaco are my favorite.

R0817, what genres of music do you favor? Jazz, pop, rock,folk, bluegrass? That would make recommendations more relevant.

Given the two you mentioned, check out

Linda Rondstadt
Rhianna
Leann Rimes
Joss Stone
Adele
Natasha Bedingfeld
Katy Perry
P!nk
Sara Evans
Stevie Nicks

Special kudos ought to be sent out to Ronstadt who, more than anyone else on this list, has successfully taken on the challenges of the various genres. Whether it's country, torch, Mexican, classical, rock, or whatnot, Ronstadt has tried and nailed just about everything thrown at her. As good as many or most of the leading ladies listed here are, Ms. R. has done it in style and a way that no-one has come close to beaing.

BTW: One more name for the lists: Annie Haslam