2. Nintendo DS - Actually, the "innovative" dual screen, touch screen, and stylus are the reasons I haven't bought a DS yet. It's gimmicky and rarely adds to the gameplay. Developers focus on integrating these features and controls, and the games are more cumbersome because of it. Yes, there are exceptions, but not enough to make me want one.
3. Immersion and Wii MotionPlus - Immersion = good. Wiimote = see above. The Wiimote detracted me from the Wii more than it attracted me. I tried my brothers, and even with the smoothing it does it still shakes all over and doesn't feel as accurate as I'd hoped. I can't imagine golf, bowling, baseball, etc being any more fun because of it. You either swing and it works, or you feel like the sensors are wrong and it fucked up your gameplay. Seems too dodgy for me to buy a system that will have tons of dodgy games that integrate weird controllers badly.
4. User Generated Content - Sure, just don't skimp on the built in content assuming the player base will create it for you. If a game has little or no on disc content and it's all user created, not only do you have to wade through mountains of shit to find something good, but the mountains will be built with giant penises and fart jokes.
7. Passively Online Multiplayer - This is actually why I prefer XBL to PC online gaming. You have a friends list that you're always connected to, and joining a friend is always at the push of a button. On the PC you have to IM/call the friend, ask if they want to play, search out and decide on a server, hope it's not full by the time you both try to connect, then talk with in-game chat IF you have it setup. On XBL you get a popup that says "soandso wants to play Gears of War 2", you hit your Xbox logo button and choose accept, put the game in, and your'e in the game lobby and voice chat.