How to Make the Most of a Work Computer

I have two Windows desktops that I use at work, however they are quite locked down on my end. They are both Dell workstations, one running Windows 7 and the other XP. I won't go into specs because you could already guess that they're pretty terrible. The experience of using these PCs could obviously be better if I had more control and better hardware to work with, but I try to make the best of it despite IT trying to tell me exactly how I should be using the computers.

I've improved my productivity and overall experience by first installing Chrome on both computers. The plethora of good web apps (including Docs, Drive, Evernote, etc.), snappier browsing, and the ability to sync with every other device I use has been a huge help in bridging the gap between what I do at work and what I do at home.

How does everyone else make the most of a compromised work computer experience? I would love to hear some recommendations on what else I might be able to do to make my time at work more enjoyable and better utilize my limited hardware capabilities.