Check out BizSpark http://bizspark.com for a Microsoft marketing program that gets startups access to the stack for zero upfront costs (yes that's carefully worded).

Microsoft has a history of acquisitions, but they tend to be based on talent, shared customers, market access or defensible technologies. Don Dodge covered this a while ago http://dondodge.typepad.com/the_next_big_thing/2005/10/micro...

You bring up a good question about the risk tolerance of potential hires. No opinion on it.