I learned that shi[f]t happens (adopted from here) - I changed several computers and few hard drives too. Most painful thing is restoring the system to the state where I can work the way I used to.

Here is what my practice to be prepared to another shift to come.

1. Outlook. I created several PST files - for feeds (How to Use Outlook 2007 RSS To Effectively Aggregate And Distill Information), for KB, for some other key things. It serves me as central KB and document managements system. I've created separate disk partition with the dedicated to all PST files folders called (surprisingly) PST.
2. Documents and other files. Not all documents are stored in OL, actually most of my docs are in file system. It is not in my default "My documents" folder but in the dedicated folders on separate partition - just next to the PST folder (see above). File system also holds all small utilities installs. When ever some program offers me storing its files in default  "My documents" location I redirect it to my one singe place to its corresponding subfolder.
3. Development and lab environments. All my development environment is on VPC 2007 stored as  VPC images - from VS2003 XP, through Vista and VS2005 and .Net FX 3, to small AD domains of 5 machines including AD, SQL Server, Certificate Services (CA), Web Services * 2.

All have to do in order to back up my files is take care of the three items above.

So essentially all I need when moving to another computer is install base image that has Windows, Office, VPC, and some small utilities which I install ongoing according to demand.

That is it - so far works for me.

What is your practice?