Those seem to be torrent downloads for the individual ISO files that make up a "complete" Debian distribution, including all of the extra packages that can be installed (but in reality seldom are). And at quick glance I think it is the "stable" version of Debian, which is an older version that tends to be a bit out of date for most uses except perhaps an Internet server.

I would suggest that you install the testing version. See here.

I would also suggest that you install from a net-install disc. You could install from the fist CD of the full Debian install set, but the difference is that if you do and you later want to apt-get something that is on that CD, then Debian will have you hunt down that CD again and swap in into your CD drive. If you install from a net-install CD (getting most of the packages directly off the Internet), then when you go to install something new Debian will not think that you have it on CD and will not ask you to swap in the CD. So for me the net-install is much better than a CD#1 install.

It's likely trivial for a true Linux guru to tell Debian not to ask for the CD after the initial install. But I don't know how to do it. (any Linux gurus are welcome to post explicit information on how to do it here.) And for similar reasons, even if I had the full set of more than 30 CDs, I would certainly not admit that to the Debian installer and waste time while it scans them all and indexes everything on them in case I want to install it later. Might be good for users with no high speed access, but for most users it is better to just apt-get what you want off the internet and know that you have the latest version than to first have to sort through discs and swap them in and install from disc, only to find that you did not have the newest version on disc.

There is also the issue of which CPU architecture do you want to install Debian for. Most people use the I386 version, which works for pretty much any 386 or above Intel or AMD cpu. But you might want the 64 bit AMD version "amd64" or some other version. I don't know if all packages that are available for the i386 version are available for the amd64 version though, I still use the i386 version.

So where do you find the current testing net-install ISO? Good question, it proved a lot harder to find that it used to be. The Net-install page has links to the net-install ISO for the older Stable version but no longer has links for testing!!! For testing it links to the Debian-Installer page. Maybe this is the testing version, I can't actually tell from the page which version it is. But I fear it could be the Stable version. If anyone knows please post. So you could either get the net-install disc from the above Debian-Installer link and hope that it is the testing version, or you could download all of the testing CD #1 and install from that. A torrent of the I386 version of CD #1 (and all of the other CDs that you really don't want to download) can be found here.