Old music
A couple of things have happened recently to draw my attention to the music of my youth, the glory days of early '80s heavy rock.

One was the installation and use of Genius playlists on the iPod Touch that I listen to at work and the other was recently getting in touch with one of my best mates from when I was at school (age 13 - 18), who is actually moving to New Zealand in the next couple of months.

Over the years my music tastes have certainly broadened, and I've even been able to totally appreciate the truly heavy end of heavy metal (the Slayers and Panteras of this world for example) now that I have started playing more guitar and can appreciate the skill.

However I'm seriously loving getting back into some of the older bands I used to listen to:

Diamond Head
such a shame they never really broke through

UFO
in the Schenker days they turned out some amazing hook ridden stuff

The Scorpions
I prefer their '80s stuff but you can't fault it at all

AC/DC
a recent revival due to the new album but the old stuff is flawless

Magnum
never gone away for me, but their old albums bear listening to rather than the greatest hits and live stuff I tend to have on circulation

Rush
stuff from Exit Stage Left and earlier era is such a personal indulgence it's a little like chocolate.

Status Quo
the older stuff up to about the 12 Gold Bars era, particularly 1976s phenomenal Quo Live

Trust
underated french band probably most noted for their song Antisocial that was covered by Anthrax. I'm still annoyed that I haven't got a copy of their "Savage" album on CD and I hardly ever play vinyl these days.

there's loads more but those are enough to get my mind sailing back to when I was much younger and the world seemed to be a much more fun place, and a time when local bands covering Paranoid wasn't simply predictable (especially when they forgot the lyrics due to alcohol and substituted really rude ones instead).