Using Workstation keeps a lot of stuff streamlined (Believe me just installing ESXi on one host is going to be a nightmare , the setup will become much more complicated and I will miss out on the occasional fun of playing some games), Using Hyper-V seems like a good idea here and will revive some old Memories of working with MS. I might give it a try when I build another system.
I have always believed that software RAID is a bit slow when compared with hardware RAID. I might be mistaken as technology changes everyday. Let me know your thoughts on it.
Lastly Using KVM won't be of much advantage as very few Corporates are using Red Hat's solutions for virtualization. One would spend a lot of time learning the stuff , just to find that no one else uses it.