Do you pre configure it for all three roles and if you need it just deactivate the two you don't need?
There's a base OS that's already installed on it, and then I would just do a fresh install of whatever I needed to put on top of that, like Apache or MySQL or whatever. Those linux package management programs have really made all of that essentially a one-command process. But again, I would have a whole different way of handling all this via redundancy if I was a bank or running something truly mission critical.