Even Greenspan recently admitted that tax cuts don't "pay for themselves" as the GOP loves to tout.
Economically, to me, it makes more sense to let them expire.
Big tax cuts encourage businesses to gouge their customers and screw their employees so they can squeeze more profits out to their stock holders.
Higher taxes encourage companies to build their equity, re-invest their profits in better tax-sheltered ways, R&D, business expansion, hiring people, pensions. Stockholders don't do so well, but it's better for the company, better for the employees, better for the customers.
Oh, but why would stock holders bother investing if they're not going to get richer off owning stock? They will anyway, but unlike the 1990's .com boom, they'll have to be a little more patient, you know, like they did before the dot com bubble.
So I say, hell yes. Let the tax cuts lapse. Tell the whiners to actually do some work rather than letting their money do all the work for them. ;)