I think we're getting a bit confused here. Upgrading your dev-tools necessarily involves pain - if you're moving sideways you'll find that #pragmas and funky syntax like __forceinline stop working, if you move backwards you'll find that new syntax stops working and if you move forwards you'll find old backends being unsupported.
It's all a trade-off.
If you need to write programs for XP, stick with what you've got or move sideways - or use an open-source CRT or a VS2010 backend if you really want the VS2011 IDE.
If, as I suspect, you have some XP users, then you need to weigh up the productivity gain of using VS2011 (i.e. the money you'll save by being more effective) versus the loss of business from XP customers (i.e. the money you'll lose by losing customers).
If money out is more than money in, stick with what you've got for the time-being. Enterprise customers on XP are living on borrowed time and will slowly upgrade out of XP or they'll be left behind by your competitors as well.