Of all the "big companies" I've seen, Facebook has the best internal IT. A lot of those policies were set by Yishan Wong; basically, if something can be done more efficiently by an individual employee than by using IT, the process is broken. (
http://algeri-wong.com/yishan/) Facebook IT is basically a cache, but if something is faster to get from the Apple Store or whatever, that's how they did it -- not sure how it is done now.
It's hilarious how in big companies it takes weeks+ to get things done in IT which could be trivially accomplished with a credit card and web browser, for less money. Yes, there are security policies (which should be enforced in the infrastructure and by user policy, not by end user hardware alone, and it should be carrot vs. stick for common builds), but things like ordering keyboards and chairs shouldn't be bottlenecked.