Core2Quad should be plenty for your hosting needs. You will find most dedicated server providers can also offer Windows 2008. If you require some for of management it is best to go with a company that is also offering other windows products.
Companies are not able to give you any deals here. So I advice you to check Offer section in WHT.
Also can you tell us the following:
2)Do you need Plesk or only windows OS?
3) Your budget
5)How much bandwidth you need, more then 10/15 Tb per month or less?