I would avoid HTIB, unless your on a tight budget or are just looking for a basic upgrade from TV speakers.
Set-ups can vary.
At the minimum, you can have a 2.0 setup, which is just a front left and right
Adding a sub woofer gives you 2.1
From here, the next step up would be 3.1 or 5.1, 3.1 would mean adding a center channel, and 5.1 adding a center channel and left and right surround.
For movie watching, 5.1 is ideal. Some movies support 7.1, but its easier to upgrade to that later when 7.1 becomes more mainstream.