Install a 1.5" conduit, or larger. There are so many possible problems, solutions and future unknowns that this is the best way to insure that you can deal with hopefully all of them. There are higher quality cables, cables with amplifiers, extenders, etc.

Conduit, just like dim4fun wrote.

Conduit will give you the flexibilty to future-proof.

HDMI will be fine, but put sweeps in the conduit run instead of hard 90's.

HDMI, for runs of 25', you're looking at a 25' or a 30' cable. Realize that a 25' cable that's 4" short does you not much good.

You can attack this on one of two ways...If you;ll only be feeding the TV from the cable box and the PS3, then you can run two HDMI cables through the conduit, one for the cable, one for the PS3. OR you can run one HDMI cable and use an HDMI switch to feed either cable or the PS3 signal through the cable to the display.

What about DVD? That will give you a third possible feed. You can drive yourself silly with the options...one HDMI cable that's fed the cable/PS3/DVD signal through a 3-way switch, or one HDMI dedicated to the PS3 and the other for the switched cable/DVD?

Your display may allow you to independently program/calibrate picture settings for each of the two HDMI ports. That may sway you one way or another.

As for the HDMI cable, for 25-30'. I'd think a good 24AWG tin- or silver-plated copper cable would do you fine. 22AWG may be too stiff to get through the conduit. 26AWG may be a bit small for 30'. Not sure though. Good HDMI cables at decent prices can be had through BlueJeanCable or through Monoprice.com.

If you end up getting an HDMI switch box, if it's not a simple push-button mechanical switch, make sure it's HDCP compliant if you'll eventually go that route. You'll need your display, your cable box, and your DVD player to be HDCP as well.

I know BlueJean's better cables are UL-rated to be buried in walls. Ask if you buy from somehwere else.

Mongo