An optimal workspace set-up is essential for making sure you can consistently contribute your best efforts. Remember, just as experimental groups invest their resources in chemicals, new lab instruments, equipment time, etc. to do their research, as computationalists, we invest in office items, software, computers, and other related tools that will make our group members more effective. So if you will use it, buy it. Don't worry so much about if you "need" vs. "want" it.