<< a friend of mine has the Z560s and I like the bass that they get, do the AL 641s get this much bass at this quality? >>
The bass quality of the 641's puts the 560's to shame. It's just as deep (actually the useable response is a tad lower), but there's some actual definition to the sound, not just a blob of low-frequency rumble. The midrange is also a lot better. IMO, the 560's put too much of the midrange through the sub, which makes the whole system sound unbalanced. It's fine for games but not so fine for music.
Don't get hung up on power ratings, that is no way to choose a system. Having more (or less) power is not the question - it's what you do with the power. For example, more efficient speakers need less power for the same acoustic output. So comparing 2 different amp+speaker setups on the basis of amplifier power is meaningless. Now if you could separate the amps from the speakers then it might make a difference, but each one is designed specifically for the speakers it is used with.
Put another way, there is no way you would be disappointed with how loud or how low the Altec's will play.
The other thing that worried me about the 560's was that in 4 out of 5 stores where I looked at them, the set on display was broken. To me, that didn't bode well for their longevity in my house, where they will certainly get a worse pounding than on the shelf at Best Buy or CompUSA.
