By Allan Sloan NewsweekApril 12 issue - Tax time isn't fun, unless you're an accountant keeping a running tab of how much you're billing clients as April 15 nears. But this year tax season's even more distressing than usual. You've been looking forward to cashing in your share of the $3 trillion or so in tax cuts President George W. Bush has pushed through in the past few years, those "real and immediate benefits to middle-income Americans'' he's promised (most people consider themselves middle-income these days). But who can figure out this stuff? Even accountants now get Excedrin headaches from...