As for "28 Days Later", its really a tough call... House of 1000 Corpses had a limited release, with a lot of hype in the horror clicks, and it did $3.5 million on 595 screens.
28 Days Later is *much* better (I've seen it), but not a whole lot of build up around it. I'll do some more research if any book posts a line on it, but I really doubt it.