Two monitors is a frivolous luxury. It has literally no actual benefit for a person competent to operate a computer (alt-tab makes this pointless). But at least a person could argue, (and they do, retardedly), that it "makes things easier" because they can read things off one screen then type something on the other, or some variation on this retarded idea.
I've got two monitors, largely for the reason descrived above -- hell, the old one still works so why get rid of it. Its pretty much useless, and the second one is off most of the day. I occasionally look at it. But its frivolous, not really a useful thing.
Cause heres the thing. A human being can never, ever, ever multitask. You are only ever looking at or interacting with a single monitor. Ever. There are no exceptions (except see below)
Having a wall of multiple monitors, if you're not multiboxing for the highest serverwide burst dps, is so fucking insanely dumb it physically hurts me that there are people who not only do it but then post it to the internet as if it was a source of pride rather than something to be mocked.
Guys check out my new rig, I have 26 keyboards, one for each letter of the alphabet. Fucking uber