I've found that dedicating the D:\ Physical drive to Linux(aka the Primary Slave, also known as "/dev/hdb," in Linux "talk") is ideal. One nice thing about having Linux on its own HDD is that I store ~400 Mb of Windows progs on this /dev/hdb HDD. Saves monumental time and trouble when my Win drive must be reformatted, which as we know occurs extremely rarely. Hah!
As to a choice of distributions. Most people get used to a flavor of Linux, then stick with it through future releases. Even though Mandrake 5.3 wasn't rock solid, I "got used" to it. So I tried Mandrake 6.0, and maybe two years later, Mandrake 7.0. Both the 6.0 and 7.0 releases did NOT like me. At all. I tried Caldera and Red Hat in the interim. Then I picked up SuSE 6.0. It was kinda weird after the Red Hat family. I got used to it, then bought SuSE 6.1. Now I'm running SuSE 7.0, which is a bit old nowadays.
To me, SuSE is what Linux is supposed to be. Rock solid, and it has very few quirks. Unlike Mandrake, which is nearly all quirks, and solid as quicksand. IMHO.