I've already done mine months ago, of course. Granted the Federal and State governments owes me money so I didn't hesitate for a second as soon as all the W2s were in my mailbox. Even if I did owe money, I probably wouldn't have waited until the last possible day like lots of people tend to do (April 15th isn't practically a holiday without reason). Because I understand that taxes, whether I owe or expect a return, is money I've already made - it isn't something extra, nor is it some sort of penalty. If I could set up my tax forms so that I end up at absolute zero (no return but don't owe any either), I totally would.
I suspect people that make a big fuss over tax day are those that haven't got their financial house in order.