I seem to recalling there are a few CAD technicians on here. Are any architectural technicians?

Ive been told we are getting new computers and basically updating everything and been asked to sort out what we need. So im after advice.

Our current set up is AutoCAD 2004 and we have 4 comps and a server.
Do I go AutoCAD 2008 or another program. It has to be instantly useable though. Whats peoples experiences with these programs.

Does anyone use Allplan? If so what are your thoughts.

Thanks

Ben