Have you used Locale? I've used it for awhile and haven't seen Tasker before.
Using Locale has made a huge difference to me. My set up is that I have two major modes, plugged in and unplugged. When I'm in plugged in mode, it turns on bluetooth and wifi, connects to my bluetooth speakerphone, and sends notifications to Android Notifier which I have running on most of my PCs. This allows me to have my ringer off and get an IM-style Growl notification when someone calls or texts, which is awesome for work. The unplugged mode is basically a typical cellphone configuration.
I've tried Tasker and PhoneWeaver but not Locale as of yet. I couldn't live without this functionality anymore.
This type of app has been one of my favorite things about Android. I can't imagine doing without it either.