My current arrangement is one that's aimed at minimising costs. I work from home, and my main machine is a refurbished mac pro. It doesn't need to be portable. I don't even have a laptop - I have a tablet which I sometimes use to take to meetings and so on.
I'm on mac and rather reluctant to switch to Windows unless I really have to.
My thinking so far in not owning a laptop has been that I get more computing power for the money if I stick with a desktop. A laptop is not