It depends on the user. Multi-monitor improvements and HyperV will be absolutely killer features for me at work (once I manage to convince our IT i.e. ). I would include ISO mounting too but that's easily doable via 3rd party unlike HyperV or multi-monitor (I don't like any 3rd party tools for multi-monitor, they always feel tacky).
While easily doable via third-party tools (I used the free Virtual CloneDrive), having it part of the OS (Windows was, in fact, unique in NOT including this feature present everywhere else) simply makes too much sense for the samer reason muti-display should be part of the OS - making sure it's not tacky and clunky.
Hyper-V is basically baked-in OS virtualization (supported in Windows hosts with VMware and Oracle VirtualBox *still* - among others, they both still work in Windows 8); however, I can say that having used Hyper-V (in Windows Server 2012, whicvh lacks the SLAT/EPT requirement Windows 8 *client* has), it smacks both VMware and VirtualBox about quite a bit (with a nurse shark). If only there was a way to add SLAT/EPT via software!
Intel's Wolfdale and later (dual-cores) and Kentsfield and later (quad-cores) have everything *except* SLAT/EPT support, which leads to the $0.64USD question - what is the lowest-end Intel processor that supports SLAT/EPT?