Not sure what Scrapbook is as compared to the Clipboard. Seems I remember something like "Scrapbook" back in PPC days... OS 8/9? There are several multi-clipboard apps around that let you save just about any kind of data from text (including formatting) to images to music to ??!! I use PTHPasteboard... when I can remember to use it!
Definitely use TimeMachine but also another cloning backup like SuperDuper or CarbonCopyCloner. They save stuff in different ways and times. I've used TM to Restore dozens of files, one at a time over several years. So far, I've never had the occasion to Start up with SD. But drives so inexpensive, why not have both methods?!
Many of us had rather know for sure what the drive is that comes in the enclosure, so we buy the two items separately. I know you are great with a screwdriver, which is all it takes to "build" your own external drive. Just get the drive with the longest warranty (5 years, as far as I know). And get one that runs at 7200rpm rather than 5400. Unless you store lots of video and or music files, you probably won't notice the speed difference between USB 2 and FireWire 800 (even with a 5400rpm drive!). Most of the time they'll mainly be doing backups, running in the background. OTOH, the USB versions will slow down other processes during those backups since it uses the cpus, unlike FW.
Your first TM backup will probably take hours. Don't be alarmed or worried! After that, they are usually done in seconds. SD/CCC backups will also take quite a while, every time. But you can schedule them for times you're not at the computer or even have them run and then Shutdown the machine late at night.