That's also a viable option. The first option I gave would give you more output, but since your room isn't that big, 4 bookshelves and a center are just fine. The Cadence isn't that big, at only 16.5" (w) X 17.75" (d) x 16.75" (h). In its price range, I can find nothing better. It goes down pretty low too, so you should really get some awesome low frequency stuff on movies and music.
You'll have to budget for stands, wire, etc. too. But this is still a great system for not too much money.
No sub isn't really an option in this price range if you watch movies (well it IS, but not a good option).