dude, the original halen is indeed a force to be reckoned with. however, van halen and black sabbath have something in common: they both started out strong, releasing 5 or 6 truly awesome albums, then their singers quit, and went on to careers that were initially successful (i.e. blizzard of ozz and that "just a giggolo" song that roth did), yet were doomed in the long-run (see: the osbournes and... well you don't see roth anywhere nowadays, do you?).
i guess that it depends on if you drink or smoke the reefer. drinking party dudes generally tend to go for van halen, while the chilled out, red eyed stoner ilk seem to prefer the slower, darker tones that only the sab four can crank out.
and granted, i would rather listen to Van Hagar than pretty much all of the post-ozzy sabbath stuff (the first record with dio singing has a few good riffs, in my opinion). but the new halen stuff sucks.
but fuckin a man. if you're into all things heavy, it just doesn't get any heavier than Vol. 4.