Hey man
I personally witnessed The Altec Lansing MX, it just blows u off if u set the equis rite. and i've also experienced Logitec Z series trust me it aint for GOOD music may be surround but thats where it stops, i aint saying its bad,its not on par with MX in quality of sound and the Shrill u wont even notice.
DeMoNvmp has DTS 5.1 now, u see the real 5.1 in action but its around 27k 2year back so now it may be 20. so if u want to have good music(say FLAC codec playing highQ music choose MX) or if u want the surround and nothing but the surround then go for Z, if u want both u have to spend a lil higher.
well, its just me........