If we knew, what fun would it be to speculate? For sucessor consoles, if Microsoft and Sony both go for "I got the POWER to RAPE YOUR WALLET" mode again, they'd probably push 1080p as the minimum resolution for their games (what was the next one, 1440p or something?). If Nintendo does the "value" concept for consoles again, chances are iffy on 1080p support methinks. HDMI would need to be on a decent number of TV's for Nintendo to consider supporting it, and unless the "surround sound" market does better, I'm not sure we'll even see a digital audio connector on the Wii.
Nobody is crazy enough to accuse me of being sane.