As far as I know, no one is forced to drop XP. MS says that they will cease sending out patches within less than two years, but that doesn't mean that XP will roll over dead.
Since some important (to me) programs won't run under Win7, I will keep at least a couple of the machines I support running XP. That will be true at least until the effort to move to newer software is successful.
If one desires to be conservative, one should disconnect XP machines from Internet access after MS abandons them.
seacue