good question. i think in the end it just comes from trying them all and seeing what unix flavor and setup that you end up liking the most.
i've done both dual and triple boots w/ win2k/redhat/and FreeBSD. they are all different and cool. at the moment i'm running Red Hat 7.1 and Win2k on my laptop here. RH7.1 is an amazingly painless install w/ no problems w/ any of the hardware. but i really think all the flavors are on par w/ each other, more of just what you're familiar w/ i would guess. though i'm certainly not a zen master on the subject. just what i took a liking to.
Here is a
link to an article that was very helpful in getting the dual boot running w/ win2k an linux w/ the win2k bootloader. it really is quite easy.
