A few basic questions..SD card / nand

Just had a couple of quick questions..

An SD card crashed a day before a key demonstration...
Pulled the plug while the OS was loading and then it went poof..

Angstrom would load in 30 minutes or so.. And give an error about some

I used a backup to get it work that day..

I would like to request more info on how stable SD cards are..

Can a system be made that relies on sd cards only like the XM. Or is
nand recommended for proper installation in a work environment and

And I've noticed that my OS (QT,Gnome,DSPLink and couple of other
stuff) goes way beyond 1gb when extracted and configured.
Configuration takes 6-7 hours!

If I am to use a nand. Like buy a revC5 with a 512 mb nand. How am I
supposed to fit a GUI OS with QT on that?

I guess I'm missing out on something basic in embedded system

Guidance please..