I would imagine your best best is Windows Terminal Services given your requirements, as vague as they are to be honest. The no virtualization thing is all your were specific about. If your users are strong/proficient with Google Docs, it might be time to just steer them to Office 365, well at least your crankiest users, for a beta and see if they can make the switch and consider that. It really depends on whether you need to host the data yourself (you say people already use Google Docs), what hardware you can or cannot dedicate, and how much money you are willing to spend.
By the way, on an unrelated topic, this is a system administration website. I know what you mean by the following.
I would prefer to deploy Ubuntu to them as it does not require any maintenance and does not need a format/install cycle every six months.
As a professional Windows jockey, I can totally relate, but that blanket comment about Linux is stupid. It is an operating system, and it will need maintenance. I spend most of my free time on Linux and Unix platforms, but a badly maintained desktop is a badly maintained desktop, regardless of what operating system. You should know better. That being said, I too naively like to believe a badly maintained Linux box is ten times better than badly maintained Winboxen, but that is probably something I say just to make myself feel better.