There are several third party apps that will return the start menu (Start8 < $5) is the one that I have used. The new start screen is not really appealing to me but I can see where MS will push the Metro Apps really hard. They want to create a profit center similar to iTunes. Win8 will run in less memory since AERO desktop is gone. Also, there is no XPMode for Win8, the Hyper-V is faster but does not support USB redirection and you do not get a free license for XPMode OS. Also, Hyper-V required SLAT and Virtual Extensions for the Hyper-V. (VirtualBox from Oracle is a replacement for Virtual PC, free). For Enterprise customers there are some other issues for mixed Server 2008R2 and Server 2012 networks.
And Yes you are looking at a re-install of OS and all applications in either case.