linux desktop from scratch?

[R. Luoma]

I need a new desktop workstation and I am trying
to figure out how to get something that will be as
compatible with one of the stock linux distros
(preferably the new Debian) as possible.

I am also trying to figure out where to purchase
the system or parts.  If I get parts, I need some
way of figure out that I get all the needed parts
and that the parts work together.

How have other readers of this list approached this problem?

-- 
R. Luoma