Oops ... I forgot to mention Skype. I've been a Skyper (???) for a while. It's a great way to chat to friends 'face to face' (using a webcam), as well as saving big $. It's use is becoming more prevalent in my work as well. I've recently set up PD for all our staff for next year, using Skype.
I wouldn't say it's as much a part of my life as my mobile phone ... but it's certainly a regularly used tool.