Re: why do people shift to debian?
I like the documentation better. It's easier to figure things out and get help. They don't patch things as much as Ubuntu does, because they're not trying to be cutting edge, so when you have a problem you can even go upstream right to the source for assistance with your problem. Not always possible with Ubuntu. E.g., laptopmode tools on Karmic.
Also, Debian doesn't push changes on the users like Ubuntu. Ubuntu pushed pulse out, and users had to figure out how to get alsa back if they had problems. Then they pushed compiz out, and users had to figure out getting metacity back if they have problems. For Lucid they're pushing out indicator applets, and the forum will soon be filled with people requesting help on restoring the old behaviour.
The above isn't necessarily a bad thing. That's what being cutting edge is all about, pushing out new things. For me though, I like to be able to choose what new things I try. I can choose ext4, but it's not default. I can choose pulse, but it's not default. I can install compiz, but it's not default. And so on.
A towel is about the most massively useful thing for fixing computers. Use it to muffle your screams when you mess up, or to dry your tears if it's broken beyond repair. When all else fails, use it to cover up the useless machine, then walk away.