Makes me sad. A bad sector on one of my HDD's wiped out my entire "D" subfolder in my mp3 folders. Goodbye Dropkick Murphies.
I listen to a lot of irish/celtic flavored music - some folk, some pop, and some punk, with heavy irish influence. Dropkick Murphies (boston irish punk), Flogging Molly (Dublin punk irish), Great Big Sea (Canadian folk pop), for example.
Some of my other favorites were mentioned above - Metallica, Moxy Fruvous, and others.
Here's some I didn't see.
DaVinci's Notebook (comedy pop - songs like "title of the song")
Diana Krall (Jazz)
Marti Jones (Jazz/Adult Contemp)
Mighty Mighty Bosstones (oh, wait, they were mentioned)
The Who (Mmmm, classic rock)
The Atomic Fireballs (swing)
Cherry Poppin' Daddies (more swing)