I consider cost and ease of access the most important things to consider for a platform. iphone / itouch, xbox 360, windows and now Pandora have pretty low cost of entry (usually 100 dollar subscription fee in the former). Nintendo DS and Wii, Sony PSP and PS3 require not only thousands of dollars for the devkits, but also require the applicant to be a registered software company with employees and previous development experience.
I want to make "art-games", but problem is the one-man gamemaker team is often lumped along with "shovelware" developers... you know, those who make massage and "fart apps".
But what if I have a passion for cinematic storytelling, but cannot overcome the technical and financial limitations? Ideally I would just release for the PC, but it would be a nightmare to market without a specific platform that is often tied to specific hardware, operating system, and comes with the benefit of a focused marketplace. (But maybe those with more experience here might actually prefer their small circle webring of indie dev friends rather than the impersonality and "billions and billions served" mentality of the Apple App store).
Nowadays, I think hardware is irrelevant (although the Pandora looks like it could really replace the netbook and PSP / DS / itouch with its multipurpose abilities -- the "only" things going against it are brand awareness (can't beat Asus, Dell, Sony, Nintendo and Apple), the reputation of linux as a geek-only OS, and content. The platforms want to differentiate themselves based on the exclusive content they have -- usually means buying out development studios who have previously released killer apps on your proprietary platform. It's kind of ironic that open-source is usually used to emulate proprietary content, when philosophically speaking the open-source environment should be the one that breeds fresh new IPs without restriction.
Anyways, it's probably still too early, but it would be nice to have an all-in-one downloadable SDK specifically for Pandora. I could still use cross-platform python-based middleware engines, but still. In the meantime I'll be tinkering with the itouch but dangit I really need some tactile buttons. Also, I really want to do 3D, but it's hard to find anything beyond FPS engines that let you import Blender models. I know 3D is very hard to do but I can still hope for some open source equivalent of the Havok or Unreal engines that you see in almost every commercial game today.