Ah an excellent question from mr. Johnston. The things that stand up and the things that don't are not always what one might expect. I still love the blues stuff on the Alllman bros. Fillmore east album and I think some of the more self indulgent stuff still stands up, like 'whipping post' and mountain jam - though the later is a bit long. Oddly enough stuff I didn't think would stand up like Spirit's The Twelve Dreams of Dr. Sardonicus, a psychedelic gem, are just as great now (Animal Zoo still kicks as hard as it did when the fabulous 'winged marsupials' covered it and the rest of the disc still gets me - "You've got a smile that turns me on") Stuff that was very poppy back in the day doesn't fare quite as well - anyone listen to their Police albums lately?- and don't even get me started on the stuff I thought was crap back then that is trying to come back like Duran Duran (although I think there might be a market for a punk cover band that changes the lyrics to be all about the Kennedys and is named Sirhan, Sirhan, but that is a totally different and much more tasteless story) Elvis Costello now ranks as one of the great songwriters for me, whereas back when he was popular I had little time for him aside from his watching the detective album. Ditto the clash - I liked them back in the 80's but they were hardly a favorite. The Beatles, the Stones, Zep and Pink Floyd still stand up, as do the Dead - though I am much more interested in Jerry's acoustic bluegrass stuff these days than yet another 80's bootleg with 'touch of grey' or 'Brown eyed women'.
I'd have to say that the bands I like in high school - largely thanks to being exposed to them by Brent and Clutton and Pentilchuk and Daley and to a large degree later on by Hoffman - are still groups that stand up now. Of course most of them were no longer popular when I got turned onto them (not many Jefferson Airplane fans around my high school in 1984, except for Compton Roberts) What amazes me are the band that were around then that I had no interest in at the time, labelling them New Wave or just plain Lame that I now appreciate like Talking Heads and Elvis Costello and Dead Milkmen.

The next question is what are all of us former sixties rock fans listening to now?