I have tons of favorite songs but if I had to choose, here you have a quick list:
Creep by Radiohead
Black by Pearl Jam
Koln Concert I by Keith Jarrett
Born Slippy by Underworld
Sometime Later by Alpha
Protection by Massive Attack
Perfect Sunrise by Orbital

No brainer for me:

Losing My Religion on Out Of Time by R.E.M.
Chop Suey! on Toxicity by System Of A Down

Well this is a tough, tough call...but some of the titles that come to mind as ones that have surely stood the test of time:
- BEST ROCK SONG: With or Without You by U2
- BEST 80s TUNE: Time After Time by Cyndi Lauper (Although I equally like the Miles Davis cover version.)
- BEST DANCE SONG: Billy Jean by Michael Jackson
- BEST CLASSIC: Hotel California by Eagles

The list can go on an on...
Atakan

The question is hard. Pick only one?? Still, there are some tracks that have made a real imprint on me. Here is a short list in no order:

- Cannonball Adderly: "Mercy Mercy Mercy"
- Mozart: Horn Concerto #2
- Gershwin: Rhapsody in Blue
- Wizards Walk: Jay Ungar (and a dance of the same name)
- Stravinsky: The Rite of Spring
- (United Mine Workers): Step by Step (as sung by John McCutcheon)
- Janis Joplin: Caterpillar (Big Brother)
... and the list goes on... I must stop typing, and go listen now :)

"Bestever" can change from mood to mood, and may simply be what's on the radio at any given moment (especially if I'm attempting to keep control of the dial from my daughter--save me from emo!!!)

However, here are a few tunes that I always enjoy--some for nostalgic reasons, some because they really are good, and some just because. They are in no particular order. There are probably at least a few dozen more--perhaps this will need an update...

Paperback Writer, The Beatles -- The first song I heard on a top-40 radio. I realized the days of listening to my parents' music were over.

Respect, Aretha Franklin

Room To Move, John Mayall

Magic Carpet Ride, Steppenwolf

Smooth, Santana

Listening for the Weather, Bic Runga

Line 'Em Up, James Taylor (all the tracks on the Hourglass album are great!)

Not the Only One, Bonnie Raitt

Learning to Fly, Tom Petty (or maybe American Girl, or Mary Jane's Last Dance, or...)

Romeo and Juliet, Dire Straits