Most future proof

Would it be one of these or another? These should all be about the same price range.

The moust future proof one is whichever one has multiple HDMI, Component, and DVI inputs and does switching and upconversion.

It should also have a network jack.

Which..if any..is that?

They've all got pre-outs and multi-channel inputs, I believe. That's as future proof as you'll ever get with a receiver. If you really need to run your HDMI cables into your receiver, I think at least 2 of these have those as well.
None have the next generation Dolby Digital/DTS decoding that will come with BluRay/HD-DVD, so I don't know how "future proof" these are...but maybe a HD-DVD player with built in decoding could get around that.

Trying to future proof HT equipment is an uphill battle unfortunately. I suspect all of these would provide you with a few more years of enjoyment, maybe more until you decide you absolutely need the new DTS/Dolby decoding, 11.2, etc...