Apple's iOS mobile operating system gets more robust and full-featured with every update. And with Apple focusing on it so much, we're actually to the point where features are debuted on iOS and poor OS X has to wait for them to make the transition over.
Two features of iOS 5, iMessage and AirPlay Mirroring, look to be in the works for OS X. iMessage would essentially allow you to IM with people on iPhones, skipping texting entirely for a real-time conversation. And AirPlay Mirroring will allow someone with a Mac computer to mirror their computer's screen on any TV connected to an AppleTV, making watching videos and presentations and reading your email on a huge screen extra easy.
Both of these ports are currently unconfirmed, but both make a lot of sense, so stay tuned.
Via 9 to 5 Mac