I actually didn't discover Facetime Audio until a couple days ago when I accidentally clicked it...I thought it was only video chat haha. Although I still mostly use Skype because Facetime, while better-performing, has a lot of connection issues (half the time it won't connect, either on 3G or Wifi). And like TheStu said, you can video conference with multiple people on Skype, which is hand with family.
I'm curious if Apple is ever going to come out with an AppleTV camera. I use stuff like Cisco & LifeSize video conference systems at work, which are basically Bluray-quality camera systems and are absolutely incredible in terms of picture quality, but they also cost an arm & a leg.
Also, I've had my share of issues with iMessage. It works well for the most part, but there's always problems when people switch to an Android phone for an upgrade and their iMessage account is still receiving their texts. I believe you have to disconnect the phone in your AppleID device list on Apple's site in order to stop receiving SMS to iMessage. This has been a huge pain for me when texting coworkers & friends who jump ship to different phones & don't receive my messages