Kim, you can tell your nephew being a hipster is very trendy right now, especially down here in Austin, hee hee.
I picked trendy because I think of "classic" as some others above, that it is something that will always be in style and is "timeless" (at least, for the foreseeable future). I agree with Julie that some classic pieces do become trendy, but I think they remain classic even though they are the latest "trend." Darn, I'm not being very clear here. I wish I could draw a Venn diagram here and show you all what I mean, lol. For example, printed pants are something that I think are trendy and not classic, but loafers are both trendy and classic. I think classic pieces would float in and out of the center patch of a Venn Diagram more readily than trendy pieces going in and out of that patch, if that makes sense. I think arty/edgy have their own diagrams. I'd have to think much longer about how they all link up together.