The successor of Wii will be less powerful than 360 in no way! If MS is able to sell an X360 for 169$ with a profit I can't see how Nintendo could not sell a console more powerful than X360 (with HDD) for 250$, especially since it will not come out before 2011 (likely in 2012 or even after).

I'd say overall yeah, though there may be "areas" it lags. Wii generally trumps Xbox overall, I imagine the same will hold true for Wii 2 against PS3.

Depends on how we define power. My guess is that the CPU will be in the same ballpark as the PS3, but the GPU, and especially system RAM, will handily out-strip it. 1 GB of RAM is a minimum, i think, with 2 as a possibility, and either way leaps ahead of the PS3's .5

Also the next Wii might still use DVDs. Not sure there.

On a second thought, maybe Nintendo will do it powerfull enough to grant PS4-X720 ports to it.

If some of the 3rd party games for the HD systems could be prted to the Wii, it would be in a much better situation in 3rd party software (not saying it is selling bad).

I would personally doubt DVD at this point in time ...

There is little/nothing Sony could do to prevent Nintendo from using a Blu-Ray or HD-DVD variant, and with Blu-Ray players regularly available at $100 today the added manufacturing cost of including this drive will be minimal by the time Nintendo's next system releases.

Yeah using DVD is pretty unlikely... especially if Blu-Ray / HD-DVD licensing fees are not that high when movie playing is disabled.

Nintendo's pretty close with Panasonic too, who holds just as big a stake in Blu-ray as Sony.   Honestly, I think all 3 will be using BD next gen.

If Nintendo do unveil a console that's on par or slightly better than the PS3, will we have a repeat of the 'these graphics suddenly look terrible even though I was perfectly happy with them for over 5 years' thing?

It will have more than you can handle.

Wrap on of these into the Wii with the infamous ductape...

...and you already outperform PS3 by 3:1 at an extra production cost of $90.