I'm thinking about getting WinXP (using ME right now and the stability is pretty poor) but have not made up my mind yet; what are the benefits to it?
Here are a few specific questions I have; some of you probably know about this stuff:

Does XP make better usage of system RAM? (I have 512MB)
How is the DOS application compatibility (I would like to be able to run some older games), and if it isn't too good, is a dual-boot setup alongside ME possible?
Does one need to buy a seperate copy for every computer in the house?
What's the deal with this "online activation" stuff? I have heard that the corporate edition does not have this thing; how much more does that one cost?