Yes, in your case the biggest change would probably be the tax tables. Also, taking one personal exemption rather than two will mean a further increase in taxable income of $3,950, and if you are taking the standard deduction (rather than itemizing) the change from MFJ to single will mean the loss of $6200 in deductions (all figures for 2014).
For couples who are now in the 15% bracket and the survivor is pushed into the 25% bracket, the increase in taxes can be dramatic (increased tax rate, decreased deductions, loss of 0% CG and dividend treatment.).
And there's the very real potential that those rates will increase in coming years to service the massive Fed debt- especially when current low interest rates rise back towards historical norms.