As others have pointed out, reducing the simple expense of dealing with our embarrassing patchwork of tax laws would be an economic boon, and I think President Bush has chosen his priorities well.
If I could suggest anything to him myself, I would suggest that we also look at reducing some spending; my modest suggestion would start with defunding the Department of Education, and work on rolling back the "drug benefit."
Looking over the "Budget Game", I whacked out $300 billion of discretionary spending in a single go. (If you are not familiar with this, it's amusing, but definitely has a marked lefty slant -- it's from UCB and its home page has a column The Progressive Populist -- and can produce quite snarky messages when you offend its liberal sensibilities about not spending enough money.) Such are the powers of play, but we have a majority in both houses, close to a super-majority in the Senate, and we have the Presidency. If we cannot reduce some spending with this fantastic position, then I don't believe that we will ever be in a position to do so. The iron is hot; let us strike.
Good list, but you left out that Kery would also have announced the cancelation of the Bush taxcuts.