Best choice between Home Theater and Logitech z906

"Good bass" is subjective.

Unfortunately the only real answer for you is to be able actually listen via the three listed options. May or may not be viable.

You may get some sense of the bass qualities via consumer reviews. But those reviews can be, and are, subjective in many ways....

Your fall back selection process includes looking for online reviews (per verified purchasers) and visiting the manufacturer's websites. Look at the FAQs, forums, User Guide/Manuals. See what people are saying, asking, and what information is provided in the documentation.

Really no easy way about it. Hopefully other posters will respond with comments and real world, experienced based suggestions - more technically based. Device problems, poor support, vague manuals, those sort of issues....

So your approach would be to consider some other requirements such as cost, number of positive user reviews, or some factors relevant to your needs.

Still there are no guarantees. Sometimes you may just have to go with your instincts and nature. And hope the product can be returned. Check on that beforehand.

monoprice 10565 or energy 5.1 classic take paired with a decent budget receiver would be better than the z906 by a decent bit.

small subwoofer included, but then again a decent sub is going to cost you almost as much as the whole setup so thats expected in that budget.

be careful of HTIB (home theater in a box) sets as many are very poor when dealing with aux input sources. some are stereo (not 5.1!) input only despite having hdmi or optical. you need to check very carefully to make sure they work with aux inputs. also, many have limited number of inputs. generally most of the cheap ones only work in 5.1 with the included dvd player. HTIB units arent all bad but you need to be extremely careful what you buy.