This. We use imaging software, and keep images for all the various hardware packages in the building. Because it's a business, all work data lives on file servers that are backed up daily. If something creeps into a machine (almost always sales people), we give the machine an enema, and reconnect them to their data. We maintain a large number of machines this way (probably over 100). It's not cost effective in terms of hardware cost AND user efficiency to use seperate machines for browsing. If we can keep that many machines, all that interact heavily on the internet, with a couple of IT guys, you should be able to adapt it to your own use.
I don't know what kind of code you're doing. Any code development I've seen requires it's own incremental backup scheme. When new code gets "sick", it's almost always self-inflicted