I’m looking forward to the 3.0 firmware in a few days a lot (although there are ways to get the it ahead of release). There are a lot of obvious holes in the existing firmware that need plugging (lack of MMS the main culprit), but the possibilies offered to app and games developers is perhaps the biggest thing for the new firmware.
gameindustry.biz has a good article on the current development situation for games developers and what firmware 3.0 means to them. I’m hopeful the new firmware will open things up to games developers such as control over the 3GS’s digital compass, which would be a massive deal for things like RPGs for example; imagine guiding Link through an adventure with an enhanced map system. Peer-to-peer will be opened up with the new firmware too, which is a massive deal for any online gameplay.
I’ve only dipped my toe into iPhone development, but I can see myself dedicating some time now towards really learning 3.0.