I.e. female solo artist or all female group. I'd probably say Lana Del Ray at the moment. Norman F***** Rockwell. Although it's recent. I think it's brilliant.
Extremelly hard to pick one...but I'm going to go with Karen James - Karen James (Accompanying herself on guitar).
Always liked: Alanis Morissette - Jagged Little Pill Stevie Nicks - Belladonna Amy Winehouse - Back to Black Patti Smith - Horses To name a few.
I can't do "favorite" anything, because it involves ranking one great song/album/artist above another great one, which makes no sense. But I can't point out an album by a female artist that I love dearly but that is not widely known: Primordial Lovers by Essra Mohawk. Apparently I can't link to the entire playlist, so I'll post the most amazing song from the album, "Lion on the Wing." But check out other tracks from it as well.