I use Linux only. My computer is self-assembled. I haven't bought Windows for it. I always find something better to spend my money on. But I like Windows.
I earn money fixing Windows problems.
I have 2 hard drives, 80 and 200GB. All my essential stuff is on the smaller drive, which is RAID-mirrored to the first portion of the bigger drive. Some of it is also encrypted using dmcrypt. The swap space is on both drives striped for higher performance. The rest of 200GB drive is for non-essential easy replaceable stuff.
I take the small drive with me when I go to work and leave the other one safe at home. The RAID just runs in degraded mode and resyncs when I'm back.
I boot unbootable PCs from my disk. It will boot on nearly any i386 compatible PC. From there I can run memtest, SMART tests to check for bad blocks, testdisk to recover partition table, sleuthkit tools to analyze and recover data from the filesystem, ddrescue to backup failing disks, offline NT registry editor to view and change registry settings, and many other tools. The only problem is NTFS write support. Captive is slow, and the native driver is still limited (but nearly there).
Booting from HD instead of some Linux LiveCD allows me to always have the best version of every tool, and newest kernel which supports every ethernet/SATA/IDE controller out there. The memory requirements are also lower.
My distribution is PLD Th, bleeding edge development branch. Its greatest advantage is that I don't need English dictionary to read or write to the mailing lists. Living on the edge means that things break and it drives me crazy sometimes, but I can live with it.