How useful is Pair Programming?
gcheong: The fact is that very few studies have actually been done so most of what you get are anecdotal accounts. 
I think pair programming has it's uses, for example, when a developer is stuck on a problem and can't move forward it's often helpful to have another set of eyeballs, but I have yet to see it effectively used full time (except for consultants who get to bill out at a double rate!).A good book to check out with some counter arguments to pair programming and XP in general is "Extreme Programming Refactored: The Case Against XP".