OK, to get things sorted out a bit:
- Trying the "stable" (Woody) branch, all you need is a pack of disks (for a quite basic system, 1-3 are a good start) and somehow an Internet connection to retreive security patches.
- Trying the "testing" branch, you sure want to have a better Internet connection - but there are daily changes, so the way I found out to be "it" is to get disk1 and do the rest via broadband. There are daily megs to get, remember, you are "testing"!
- Trying the "unstable" aka "sid" flavour requires the same as "testing" aka Sarge by powers of two. No Broadband? Don't try sid, you won't love it.
Sarge will be the next "stable" flavour soon (the default answer is, "when it's ready", but I expect it to be stable within some weeks or months), so what I write now is not applicable anymore when Sarge is in "stable" state.
Stable means, no changes in the combination of packages are made anymore, but not that the box behaves windowish and crashes;-)
BTW: Knoppix gives you a nice test drive of debian, so if not sure if it matches, get Knoppix first.
Another point: the first CDs are all bootable with different kernel "flavours": vanilla is the most stable, but also the most dumb one, for most PC hardware the "idepci" will give you a good rescue, and for the usual PC stuff, Disk1 gives you a state-of-the-art kernel with support for almost everything. bf24 is a 2.4 kernel used for booting.
Guess what the disks for "compact" is used for?;-)
So, if you get into trouble, there is/should always be a boot disk getting you out of the mess.
Having all disks, you have all the packages included in the distro. Having less than that, there are some packages missing. The Debian Guys made a great job putting the "important" and "usual" packages on the first disks, but, alas, if you want something special...
On the other hand, with a fast Internet connection, Debian is absolutely fantastic: Looking for a pack / a command? apt-cache search gives you the name, apt-get install gets it into your box, resolving all the library and version tweedeldees by itself that costed some good men the best of their nights ;-)
I hope that I put a little light on some things.