What are the goals of the system?
If they are mainly for reproduction of movie scores (specifically action movies, like Michael Bay stuff) then you really, IMO, can get away without spending all that much money.
I have a Logitech Z4 system wired with a RCA Y-jack into a 1/8" stereo jack adapter for my 42" Philips LCD. This is the system:
It fits nicely behind the display, and provides enough punch. The speakers on my LCD have an adjustable delay, so I can mimic "surround sound" and center channel placement with settings. If you find the speaker set on sale, like I did, you can pick it up for $80. It sounds "good enough" for movies.
What anyone really needs for normal movie viewing:
-Decent center-channel source. Most newer displays come with speakers that can fulfill this role without problem.
-Decent two-channel with sub combo. Most better quality computer speaker systems will meet and/or exceed these requirements. These can hook right into the display with a Y-adapter (mentioned above) into the output jacks. This eliminates the need for an A/V receiver, and/or any other auxiliary nonsense. It also creates a "cleaner" setup, one that the wife/significant other/parent would appreciate.
IMHO, the x.x (5.1 to 9.2) systems are really number wars. They add very little, acoustically, in a small room (anything under 30'x30'). A finely tuned "3.1" setup with a center/left/right/sub setup with decent fidelity and minimal distortion will be impressive in all but the most extreme situations. Don't get caught up in watts per channel. THD (total harmonic distortion) and speaker efficiency is far more important. Most boxed systems suck in both regards.
Don't drop the money on Bose. Bose is not highly regarded in either the high end market for quality, and is not priced competitively in the standard consumer market. "No highs, no lows, must be Bose" sticks around for a reason.
In regards to wireless speakers, you are dealing with two issues: Limited power supply, and limited signal fidelity. I would try to avoid wireless units.
For reference, I have a separate audio system in another room for accurate music production. It consists of Polk Audio LSi9 speakers, a separate subwoofer, 2-channel amp, old school (but high quality) CD player, etc. I have no problem putting money into that system, but for TeeVee and movie watching, I have found that my under-$100 solutions sound 95% as good in normal, non-deafening, smaller (12'x15') applications when compared to any boxed-surround-sound setup.
In regards to wire gauge. This is a pet peeve of mine. Gauge should be selected in regards to the current output, resistance, and voltage of the system. Most people are way into wire size in regards to speaker systems. There have been tests done with coat hangers as conductors with "audiophiles" listening and most couldn't tell the difference between a coat hanger and the highest grade "Monster Cable". Shielding is far more important in cabling, especially if you live close to broadcast towers. Most systems are fine with 18/16 gauge wire. Even running 500w discrete channel amps would only require 14AWG cable.
IMO, if you are going to build a system for music, with watching movies as a side benefit, then invest good money if you want to really hear your music. If you are investing in a system just to watch movies, then get something appropriate that works well in your space, and save the money for the real system. Furthermore, most rooms that are setup for movie watching aren't great for audio. I am against spending large sums for a surround sound system, mainly because they do very little in enhancing the movie experience in a normal family environment.