Just be careful about creating a ground loop condition from doing this, unless all grounds in your house are terminated to a single point you are introducing the chance for a difference in ground.
Also you can get transient voltage from Cat5 or Coax cables going straight into your PC, cable or satellite set top boxes. If you surge protect everything but not those inputs its just another place for the voltage to seek ground.
I got my Shimian 2 days after ordering from ta_planet for $328 and couldn't be happier, only problem with my unit is 1 dust particle in the lower left quadrant but its hardly noticeable, for the price I am ecstatic!
Why not run HDMI straight to the projector and a separate audio feed? There are devices out there that will strip analog audio from HDMI and then pass the HDMI on to the display.
There are quite a few options these days, the monoprice units are actually very decent. I tend to use a few different brands but have had luck with most of them as long as good termination is applied to the wire.
SirMaster makes an excellent point, speakers have not changed much in form or function over the years and are a sound investment that can last a long time.
I actually have 2 pairs of speakers that are older than a lot of users on this forum including myself and they were more than $150 each...
There are good sound bar units out there, but they don't cost anywhere near as low as the $300 limit. Leon speakers make some great sound bars as well as other speakers but they are not cheap as the tweaters and midrange drivers they use cost more than $300 wholesale in some of the units.
The advantage for daylight viewing is diminishing with LED's vs Plasma as many of the newer models are coming with Glossy screens just as reflective as Plasma glass.
Samsungs produce a good picture but have an astonishingly high failure rate. LG is good in their higher models but the lower...
I would get some good near field monitors and a decent sub, this should be well under a $1000 and perform better than any computer setup and still be self powered for easier hookup. Next step would be B&W MM200/400 and add a sub.
I would go with the $56 on assumed build quality of the pictures and the fact that it actually states it can output 1 source to 2 displays as this is not always the case with cheaper HDMI switchers.
And even after CES most sets don't actually make it to market until Feb/March at the earliest, nothing significant would be my prediction from what I have heard from various reps trying to get me to pickup the lines lol.
Check out the MSI options, I have the GT780DXR and love it, though its about 300 above your cost for my configuration. There are a few models that should fit within your budget.
I built a new htpc with the same board, processor and a 64GB Crucial M4 SSD for cache and it has worked very well so far without any issue. I have never had problems with Gigabyte boards even if they aren't the fastest.
Acoustical foam is designed to decrease reflections in a room, not help prevent transfer of sound to adjoining rooms. The best way to prevent sound is to isolate the room or move the source, since you don't want to do either the compressed fiber board will be the next step, if you want to get...
I have had to cancel 2 orders recently due to ridiculously extended "processing times' despite paying for expedited processing and overnight shipping, last order was still waiting at the processing stage after 6 days, with calls made by me daily after the second day.
I used to love ordering...
If you want the quickest cheapest way, go to home depot and buy a sheet or two of a compressed fiber board, the stuff used to make A/C ducts and cut it to shape and cover it with fabric. I would be amazed if the tv speakers were able to transmit much through the walls alone.
So far its ok, not great and not bad either. The trackball seems to not responde all the time but could be a few things including distance limitations. I'll see how it goes.