I read with interest this article "IT heresy revisited: Let users manage their own PCs"
by Tom Sullivan. I think it's definitely a good idea to look into having users dictate which PCs they use and how they manage them.
Because specific applications and hardware appeal to users for depending on a variety of features, they're usually not best doled out in cookie-cutter fashion to all members of an organization. It would seem that companies like Google and BP may be on the right track by giving users more say in their PC options. I liken it to respecting, rather than insulting, their employees' intelligence.
Naturally, certain aspects of IT shouldn't be left up to all users - certainly in conditions where security and confidentiality are key issues. That's where companies have to set limits and offer ranges of options within a spectrum. Parts of IT just can't be delegated - that's where savvy organizations will have to strike the right balance between giving users more say and keeping standards that can only be accomplished via one central modus operandi, if you will.