I think anyone who sees it who is under the age of 40 (not saying older people won't like it) would love it. I don't think there has ever been a show as perfect as Freaks and Geeks. In one season they were able to create meaningful characters and all of them are trying to find a way to find themselves and each of them have a different way of doing that. It's really amazing. The only show I've seen that comes close to capturing that is Friday Night Lights and that doesn't really come that close. It's still good but it's no F+G.
Speaking of Friday Night Lights: Did it get cancelled?
FNL's 3rd season premieres in the fall on DirectTV and then I think NBC will re-air those episodes at the beginning of 2009 (at least I'm pretty sure that's what I've read from several different sources.
My girlfriend watched F&G for the first time last summer and we had a discussion about whether or not a second season would've been a good thing for the show. I go back and forth on it a lot but I've come to the conclusion that while I would've loved more episodes, it's just perfect the way it is.