I'm developing a pretty portable indie game engine and also a "demo" game to go with that. In the future I would however like to make a more comprehensive game to deploy on some different platforms. The details on the future game is less important, I'm more into the "how" than the "what" -- genre and content is irrelevant to me.
So what target platform would you recommend? And what cheap features (which rocked immensely) have you successfully developed for that platform? Please keep cost-effectiveness in mind, since my budget won't allow for purchasing SDKs with price tag of 10k U$.
Edit: I am really interested in what cheap features you have successfully developed for a certain platform. E.g. "I made this awesome two-finger-touch-input-control-method-for-a-retro-type-this-and-that-game for iPod in no time and it rocked -- I can really recommend that platform/approach!"