Food for thought.....
HDMI for the DVD player will yield better results than the cable box. There's really not going to be a significant picture upgrade from cable if you go HDMI. DVD will give a better picture, however, if you have an upconverting DVD player.
Because you have a projector, which typically only has one HDMI or DVI input, HDMI switching is an important thing to have. Having mulitple inputs on the receiver will allow for more options long term. However, you could run one component and one HDMI from the projector to your equipment closet and that would always allow for an HDMI connection device down the road.
Even though you've never had it before, HDMI will be important long term for obtaining the best picture possible from sources like TV, DVR, cable box, video games, camcorders, etc.... at least until something else better comes out
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The best of both worlds.... don't get a receiver with HDMI switching right now unless you will have multiple HDMI sources to switch between (which said you don't). Run a high quality HDMI AND DVI cable as well as a component video AND Cat5 350mhz cables. That should be perfect. Then, this is the cool part, down the road when needed get a little video scaler from a company (DVDO for example) that will convert all analog connections as well as allow for mulitple DVI and/or HDMI connections. That way you can get the best picture possible, keep the video away from any processing that the receiver will do (which is almost always a good thing), and save a little coin now.