Lately, I'm doing Rails development. Using Git, RVM and Bundler makes re-deploying my development environment a piece of cake, so I just make sure to have my source code backed up.
The price to pay for this is that booting and local file access is, on average, an order of magnitude slower than with an SSD. Even over gigabit ethernet the latencies are killer. This is not generally a problem once things are set up, though; my code is on the RAID anyway so the only additional latency is when some config file falls out of the cache and has to be reread.
(Remember, though: RAID Is Not Backup. My homedir is backed up nightly and snapshotted hourly.)
I can get running on a new computer in a couple hours; I don't have to hunt for licenses because they're in 1Password, my editor configuration is on GitHub, and the applications I use are stored safely at their vendors' sites.
Getting photos and videos back after a failure will probably take days, but that's what I'm willing to pay for, and it's better than never.
I can get back to work in time it takes ubuntu to get installed. There would certainly be things I would lose, but nothing I couldn't live without.
edit: I don't backup my dev machine for the above reasons.