This has probably been covered in this long thread already, but the reason many people are so critical of Bose speakers is that many of them do not and *cannot* produce certain frequencies. Sound is nothing more than vibrations in the air, at certain frequencies. Most humans only hear from about 20 Hz to 20,000 Hz or so. That's why you see so many speakers claiming that they are capable of reproducing frequencies in that range. If a speaker is not physically capable of reproducing frequencies in a certain range - say for example below 130 Hz - then when the program material to which you are listening, be it a CD, a DVD, the radio, etc., has sounds in it in that range, you simply will not hear them (i.e. you won't hear the deep rumble of an explosion in a movie).
Therefore, with your Polk speakers, for example, if you are using them with nothing else (with no subwoofer, for example), you simply will not hear any sound (bass) below 130 Hz. Since most of the LFE (Low Frequency Effects, or the .1 in 5.1 or 7.1) are in the 20 - 80 Hz range (and many newer movies contain bass information that actually goes down to the 15 and 10 Hz range), you're actually not hearing *anything at all* if you don't have speakers that can play down to that range.
What all of this means, and what is germane to the discussion over the last couple of days in this thread, is that if a speaker is inherently unable to play certain large ranges of frequencies (like several Bose products), it is *by definition* inferior.
Then there is the whole other discussion of subwoofers (which you'll find in several forums here and other places, like HT Spot). One might *think* one has a decent subwoofer and feel pleased with its sound, but it may not even be playing a whole, vital range of frequencies necessary to a true theatre experience - typically frequencies in the 15 - 40 Hz range, as most cheaper subs are lucky if they can even get down to below 40 Hz. On top of that, if your satellites can only play to about 130 Hz, you are getting *very* poor integration with your subwoofer, since any frequencies above 80 Hz are localizable (you can tell the sounds are coming from the sub and not the satellites, therefore making the listening experience artificial and more contrived). There are several threads on this too, which you can find with a search.
I'm not trying to belittle your system or your ears, but while you may feel you are getting "great bass" and good sound in general from your system, if your satellites only play down to 130 Hz, and if your subwoofer is quite inexpensive (and therefore probably cannot play below 40 Hz), you're not hearing the program material as it was meant to be heard, and at the very least you're not getting "great bass." I'm also not trying to belittle you, but I would have thought an engineer would have known most of this. (Maybe your engineering degree is in a much different field?)