I'd say go with the OS that you know the most about and have the most experience with.
Offtopic: Nice slogan Jim, but you can't have my domain... businessclasshosting.com LOL
Or my no. 1 google listing come to think of it!! <a href='http://www.google.co.uk/search?sourceid=navclient&ie=UTF-8&oe=UTF-8&q=business+class+hosting' target='_blank'>http://www.google.co.uk/search?sourceid=na...s+class+hosting</a>