I love Herman Zimmerman's take on the Enterprise-D, it's bridge and hallways. Hated the engine room with a heart-felt passion and just about everything else Herman ever did. "Z" is a lovable guy, a sweet soul. But I hate his design sense, for the most part, which is all up in DS9, everywhere you look at, on and in the station.
I don't think there's anything I don't love about TNG's interior designs. The engine room was the most kick ass room of all though IMO.
DS9's design hasn't really grown on me at all. I think the station outside is this hideous spider looking thing, and inside looks like some neon Tokyo/Blade Runner inspired sets. I let it slide because it's supposed to be "alien" (Cardassian design)