Web 2.0 design, like Web 2.0 itself, is such a flimsy concept. I personally think it's thoughtful whitespace, careful colouring and icon sets, but everyone's got their own contributions to make. That said, Standards are King, most definitely, so my pitiful excuse for a suggestion is A List Apart, a duh! entry, although it may be closer to the techie/IA stuff than something more aesthetic that you might be wanting. I think there's something to be said for shifting around enough within the design constraints to have something beautiful. But if you start only with the appearance first, then you end up bending some function to suit your design (which may or may not be what happened with that TIFF site we harp at so mercilessly).

Anyway, I hope you're able to use whatever examples you get to convey the approach and mindset, because that's undoubtedly way more important for anyone to be leaving school with. Unless they're scared even after 4 years of school, in which case I feel for them.