I currently own The Sims University and Nightlife, i agree, the Christmas Party pack isn't very good. I don't really play The Sims anymore though, when i first got it, it was so addicting *reminices* (or however you spell it)
I have the Sims 2 with all of the expansion packs. The Christmas party pack wasn't as good as I thought either, and I also thought Open For Business would have had more objects and accessories than what it has.
Nightlife is really good. University is good as well although it does become difficult getting everyone on the lot to do what they need to do without two or three flunking out.