Multi-Monitors and Increased Development Productivity?

cK-Gunslinger asks: "I'm looking for some definitive, legitimate studies/research that show that using a multiple-monitor setup yields increased productivity for code development. (or disproves, as the case may be.) I've seen many online 'articles' that praise the virtues of multi-monitor setups for content creation and HTML editing, but my interest lies more in the OO design, coding, and test realm. Sites such as RealTime offer some good info, albeit not completely unbiased. And who doesn't drool over X-Top systems. I'd like to submit a proposal to our IT and Process groups recommending a "trial run" on some small project, but am having a difficult time finding enough empirical evidence to crack the budget-clench. I'd also be interested in user comments on how multi-mon setups have helped your productivity as well as how you typically use your setup (what apps, how many monitors, CRT vs LCD, etc.)"