Having used mainframe dumb terminals (I've even *whispers* done some mainframe programming in the past) I'm not totally sure why you'd want to do this with a PC. PC's work fine as they are. If you want some central control over them this can be done with network software from experienced companies like Novell or Micro$oft. Trust me I've seen it work.
Most of the items in the top 10 that I remember are more than worthy of their place, I'm not sure about VoIP though. Years ago when most connections were modem based VoIP seemed crazy, but now it not only seems more practical, I've actually seen quite a few sucessful installations with some smart looking Cisco kit.