Debian is thought of as one of the most stable distributions... but that also makes it a little behind in upgrades. Unless you decide to follow the "testing branch" or the "unstable branch" which is updated more often.
I myself would run the stable branch on a 24/7 server and "testing" on a desktop compuer. And then I would run testing or maye unstable on my home computer since I know how to fix things...
AND "testing" is regarded at least as stable as Mandrakes distribution... ;-) Debian Stable is for those who want a rocksolid distribution... and BTW we will soon get a new stable... the current "testing" branch will be considered stable when it's been tesed enough.
If you just want to play with Linux I'd recomend KNOPPIX and you can actually use that to install Debian... quite a bit easier than the debian installer I guess... but once you have installed Debian you don't really have to do it again... My Debian installation on this computer is probably about 4 years old. But it has been upgraded over time... but I haven't formated my drives and started over. But I have moved my installation between drives when I have upgraded to bigger harddrives...
There are also several debianbased distributions that are easier to install. This is the last one I heard of:
http://www.ubuntulinux.org/But there are several others...
/LinuxSam