You need to run at least 1.25" conduit if you are setting up any video location. If you are running HDMI now, I would NOT run it in conduit unless you have to. Leave the conduit empty until you need it and run a few pieces of HDMI (if you can) and several pieces of CAT-6 cabling as well. This way you really are covered from the start.
Generally 'orange' is the color to indicate low voltage, and you can pick up orange low voltage conduit by the foot right here:
Ipex USA KPHxxxC Series. KwikPath Resi Raceway - HomeTech Solutions
The shipping is always a bit pricey, so you may (MAY) have better luck checking with a local electrical warehouse. If you are in the DC area, I keep 1.25" stuff around typically and could hook you up with 15' for cheap.
There isn't much in the way of 'boxes' for 1.25" stuff due to the size, but I typically wire-tie them in place near the box or to the box as necessary. Just so I can get to them later.
They do have a double gang new work box with a 2" conduit fitting on it:
OEM Systems OE-MR22 2 Gang Mud Ring, With 2 2 inch smurf conduit - HomeTech Solutions
They also have plenty of other connectors on their site. Not always the best pricing, but they have a pretty deep selection available.