Rock:
Eric Clapton - anything by this guy. He was in Cream, Derek and the Dominoes (hint: Layla) and tours solo. Amazing blues-rock guitarist who knows you don't need to play fast to play well.
Jimi Hendrix - similar. Anything by The Jimi Hendrix Experience is worth listening to - if only to find what didn't work. Purple Haze, Little Wing, Angel, Hey Joe, Voodoo Chile, Highway Chile, Red House, Crosstown Traffic (featuring Hendrix on the Kazoo) - all great tracks.
Dire Straits: some brilliant songs, some rubbish. One track that springs to mind for brilliant is Sultans of Swing.
Very nice listing. (I omitted Muse - I know a fair few people who hate them and they're major rock lovers. I like them, personally, but I find that it's kinda 50/50. I'd call them their own subgenre, personally)
Imma throw in some songs. I find them to be staples of my musical diet, but then again that might be personal opinion.
Norman Greenbaum - Spirit in the Sky
- - It's got quite the Christian message to it, but I know a couple of anti-Christians who love the song, so that kinda tells you something about how good it is.
Ronnie James Dio - Holy Diver
- - Dio's stuff might be under the radar, but he was one of the best voices in Metal (until stomach cancer had it's victory, RIP Ronnie). And he's got quite a career record - Rainbow, Elf, he was even with Black Sabbath for a bit.
Black Sabbath - Iron Man
Black Sabbath - Paranoid
Ozzy Osbourne - Crazy Train
- - It's...Ozzy. Come on. Do I really NEED to explain this? EVERYONE loves Ozzy.
Metallica - Enter Sandman
- - Quite possibly one of their greatest hits. Starts out kinda calm, then starts building noise up until KABOOM!
Led Zeppelin - Stairway to Heaven
- - Led Zeppelin's best selling song. BEST. SELLING. Fun fact: They spent a long time trying to figure out what this song was about, then the guy who wrote it spilled the beans - it wasn't about anything at all. Dude was making it up on the spot.
Eagles - Hotel California
- - Calm. Deep. Moving. Makes me think of LA. Which is good, because it was about the dark side of SoCal lights, fame, etc.
Nightwish - Ever Dream
- - I SWEAR THIS IS ONE OF THE BEST SONGS EVER WRITTEN. It runs freakin' chills down my spine, and not many songs do that. It's both happy and unhappy at the same time, somehow. It's...AMAZING.
I probably have more. I can't think of them.