I work deep in IT (information security) and spend 90% of my working time in the browser looking at our security monitors. Another 5% in Word preparing memos or taking notes. The rest is split between the command prompt (nslookup, ping, basic stuff), Excel, OneNote (time/project tracking), SSH, and that's about it. Everything else I do at work is personal stuff done on personal time at the office.
I'm not a boss of anything or manager of anything. Programmers will always need computers targeted to whatever they are programming to, but I would guess that most other IT workers would be fine with a browser and Office (except stupid legacy apps that your office makes you use that were written in Java, talking to VB6 which really only interfaces with a database. You know what I'm talking about).