"Scientific Linux? What's that?" 
And while there's probably nothing wrong with the OS or its pedigree,
that (semi-amusing) question is pertinent, I think, for someone in his
position: he doesn't know much Linux, and is willing to do some of his
own legwork on the support front, in exchange for not having to pay a
fairly sizable yearly support charge.
In that situation, the more public resources there are on which you can
draw, the better off you are.
For you and I, something like SL (which I do remember seeing go by on LWN
a few months ago) would be a good bet. I'm not sure that's true for
someone like our OP here.
Cheers,
-- jr 'deja vu all over again' a