OK, I'm going to approach this from the perspective that the bands must at least have had some kind of success, i.e. bands people will have heard of:
The Charlatans - some great tunes, and IMO could potentially have taken over the mantle from The Stone Roses.
The Goo Goo Dolls - slightly strange choice this, as they are quite famous on the world/internet stage. But ask your average man in the street in Britain to name more than a couple of their tracks and he will struggle. That's quite shocking for a band that has been around as long and made so many good records.
Natalie Imbruglia - Doesn't have the same pull as many top 'rock/pop' female vocalists, but having seen her live, she is genuinely talented. In my view she is easily the equal of the likes of Sheryl Crow or Kelly Clarkson.
Jewel - Truly outstanding singer/songwriter with a beautiful voice; sadly her recent work doesn't really match up to what she did in the 90s. She's not received as much acclaim as say Katie Melua or Joss Stone but is vastly superior.
Third Eye Blind - Everyone knows Semi-charmed Life, but that's probably not even in their top10 tracks. I guess they are regarded as a one-hit wonder with a Spin Doctors sound, when in reality they made quite a diverse range of different, quality songs.