I have a HDMI-to-DVI adapter (I need that to plug it into my HDMI-less monitor), so that's fine, and yeah I could use that solution for the PS3 but that screws me for the Wii U. I don't trust Nintendo to have a separate audio output option, no matter how logical it is. Plus, end of the day, it would be easier for me to pug in headphones directly than find my speaker set, plug in the speakers via RCA, then headphones into there.
I do most of my gaming on PC already, but I'd be tre pissy if my TV were to pack up when, say, Rising came out.
Not the cheapest solution, but you could just get a receiver, most let you input audio/video how you want and then output to whatever connection you want.