Sytem advice Upgrade? Help!!

I currently have Nakamichi AV-7 an mb-10 cd player and a set of B&W dm620s. I have the chance to upgrade to seperates starting with a B&K avp1000. Questions I have are: what amp recomendations(I will probably want a multi channel amp) Can I go with a tube stereo and then a 3channel amp for surround. Is this a decent upgrade? Help!!