An Onkyo HTIB is a good bet if you want to get a 5.1 (or higher) system. ShopOnkyo had the refurb 7.1 790 set for $249 last time I checked, which is a very good deal for a system like that which is basically an Onkyo 504 receiver with a basic 7.1 speaker set.
If your primary concern is audio quality though, an Onkyo set probably wouldn't be the best way to go. You get good bang for the buck, but a good set of bookshelf speakers is going to be significantly better than the kind of speakers you'd get from these HTIB sets.
If your priority was a 5.1 set on a budget, then I'd strongly suggest looking at HTIB options from Onkyo, but if a quality 2.1 set is the goal, it might not be the best way to go, especially if you're not even going to use most of the speakers.
On the other hand, something like the 790 set would get you an adequate subwoofer and the receiver would be pretty decent too. You could try the speakers too and use them if you find them adequate. They'd certainly make decent enough surround speakers too if you decided to upgrade the front three speakers down the road.