I've just had too many other websites close with no warning in the past (Working Designs). Granted, they didn't have my money online, but still...
I'm not mad though, just momentarily annoyed. I'll probably be even more likely to buy games from them. Who knows when I won't be able to get them. This trick works on me to an extent.
Definitely downloading and backing everything up as soon as I buy though (advice previously given).