Of your options I would recomend Mandrake. I have used Red Hat and have 
built my own. Red Hat was a bit more difficult to figure out and Mandrake is 
really simple to configure. When it comes to support Red Hat has the most 
documentation availible, thats my opinion, and is easy to upgrade. 
Mandrake's mirrors are usually down and are rarely updated, I mean that they 
are hardly replaced. If you really want to get into linux and learn all 
there is you should read "From power up to bash prompt", search google to 
find it. And build your own linux using www.linuxfromscratch.org. check it 
out.

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