Beethovens 9th, 1812 Overture, Any Wagner is good, Mahler too, the heavy stuff.
For just cruising you could kick back with Bach, or Handel if yer more the arrogant type, but Brahms and Chopin are right out (jeez I hate chopin).
But whether it's yer 1970 AAR Cuda or yer Old Tomos, nothin better than windin it all the way out to the Choral Harmony version of Mr B's 9th symphony.
Besides, you can head-bang to the 9th, if yer really hardcore, I've seen it done.
-Ree