Okay... I just put 3 windozes (98SE, 2K Pro, XP) and one SuSE on my 30gig last week.
For the newer distros (and to allow for more apps, etc), I allotted about 8gig. All the stuff I downloaded took up about 1.5 - 2gig. Technically, you can run linux totally off a floppy with some distros...

But for what you need, you can do very well with a 10gig partition.
Regarding which one - that will ultimately be a personal preference. There really isn't a "best" flavor. They all pretty much use the same kernel, but make their installers different from each other and bundle different apps with their installs.
If you want, why not try Caldera's latest (2.3 IIRC?).... since you're already familiar with Caldera. I had tried the 2.2 on my 486 (a mistake...lol), but it wasn't bad at all. I just had some issues with X and my old Sigma VGA Legend 1MB RAM card... heh. I went back to Caldera's 1.3 version permanently for the 486, which runs just fine.
People will mention Debian (a bit tricky), Mandrake (supposedly newbie-ized but IMHO, its RPMs are propriatary...

), Red Hat (been around awhile), SuSE (been around awhile too), slack (seems to be a favorite all around - an old timer). Hey - you can even give Corel a try (although I think they decided to give up on the "linux desktop" thing...lol).
Again - try the newer Caldera and see if you like it. I don't hardly hear anyone mention it, let alone report on it, and it would be nice to get some comments on it.
