The touch screen doesn't do much for the DS, it's just that the stylus needs a touch screen for that stylus to work properly with games.  With that in mind the Wii is nothing more than a DS with T.V. out and one less screen.  So to answer your question incorrectly the Wii is the home console with a "stylus".

Brain Training is one of the biggest system sellers of all time. Without a touch screen, Brain Training would be nearly unplayable. A touch screen or keyboard is necessary for any games that require text input. Trying to type in text quickly with knobs and buttons is painful and pointless.

Precisely! Well, not precisely, it's wrong your comparison, but I agree on one point: The wii is something like the DS. It changed videogames at their core: way of control/gameplay.

The DS and wii haven't changed gameplay in any fashion. The best games this generation (mass effect, demons souls, uncharted, STALKER, TF2) don't use touch screens or motion controls. The wii and DS were a revolution in that it expanded gaming to casuals. Sony and MS have their motion control devices on the way, and their key developers (bungie, naughty dog, etc.) have already said they won't be the utilizing it. So what are we going to get when they launch? Fitness games and casual titles. And thats fine, but its not changing gameplay in any significant way. The input method for a game has nothing to do with the quality of the game, and having a new type of input doesn't make a system better than one which uses standard controls. For instance wii sports, which uses motion controls, its pretty terrible. L4D, with standard controls is pretty awesome. On the flip side, Terminator salvation with standard controls is terrible, while mad world with motion controls is good.

As for psp and DS, Loco roco and NSMB are equally good games, and are both mini console games, the fact that mario has some touch screen action doesn't suddenly elevate it above the status of being a console 2d mario that fits in your pocket.

I'll agree with control, but not with gameplay.  Though that's a discussion for another thread.  On another note I actually agree with Leatherhat, but again a discussion for another thread.

Price is a major factor in me not getting one.  But the gave up too much to go for a smaller form factor.  UMD is gone yet price is up(strike 1).  My UMD library isn't transferrable(strike 2).  I own a small cache of memory stick duo which is now totally useless in the PSPgo(strike 3).  The reasons to own a PSPgo has been pretty much nullified.  I'll have to hold out until Sony does a PSP 2 or something like that.  A relaunch isn't going to make me want one more than now thats for sure.