After reading:

Black Sabbath - Liked some of the songs, like war pigs, paranoid and the one about the jet fighters
Deep Purple - Who? (I have heard of them)
Rush - Who?
Led Zeppelin - They are great, but I'm not that big of a fan
ZZ Top - Have 'Tush' but not heard anything else...
Budgie - Who?
Queen - Who? Kidding! They are AWESOME.
Iron Maiden - Also awesome, but not keen on the new album.
Ynqwie J. Malmsteen - Have one track but I seriously want to get more.
late in this ( ) thread, it occurs to me that we older metalheads may not be doing the best job of passing along the history of our preferred music to the youngbloods, especially those who came to the genre alone and without guidance.

I laid down some basic background info on Black Sab, Rush, Deep Purple, and Budgie in posts #167 & #169 in that thread, but I know that's not an exhaustive list of important foundational bands.

So, Old-School Metalheads, lay down the knowlege for your younger bretheren- who should every metalhead know and respect for their contributions to the genre, if not actually enjoy, and some of their key tunes.