About 50 feet for HDMI cables distance - with good cables. I would pick up a decent cable at
www.bluejeanscable.com, though if your access is really easy, you could check
www.monprice.com
If you have EASY access to run cables in the ceiling, then just run the one HDMI cable now and if you need different ones later, then run them later.
I recommend a run of composite video, component video, and HDMI video. But, this is for drywalled ceilings that may be very difficult to get to later.
If you have all HDMI equipment and a HDMI switcher, or if you have a receiver that upconverts to HDMI, like the Yamaha RX-V2600, then you don't need the other cables. But, I consider them good to have, just in case.