If you've got your Vivid, you can use HTC Synch to synch your contacts from Outlook. If you're using Gmail, and have synched your contacts with them, they're in Google's cloud and can be re-synched from there. The main thing you've got to back up are your pictures, videos and music. HTC Synch can handle putting those on your computer. I've been reading the full Vivid user manual in advance of getting mine. I intend to use HTC Synch and HTCSense.com to their fullest to keep my data backed up. I Strongly recommend downloading the full manual from the HTC site. All you get from ATT is a quick start guide.
As for your apps, if you got them from the Android Market, you should be able to get them back from the Market just by logging in. I got that tidbit from a long time Android user friend.
The main times you have to worry about backing up is for a clean OS install, factory (hard) reset, or if you wiped it from HTCSense.com. Just keep it synched regularly and you should be good.