I personally don't see it as theft (can't personally make the leap), but I can see how others do.
The problem I have with taxes is 1) what they are used for and 2) how they are collected. Regarding #1, I'm perfectly willing to pay for the "price of civilization" stuff (military, police, courts, etc.); basically the stuff explicitly outlined in the Constitution. I don't like paying for transfer payment/social engineering-type programs.
I also have a problem with the concept of an income tax. The money that is withheld from your paycheck and you don't get back in a "refund" (so Orwellian to call it that) is, practically speaking, never yours even though you worked for it. Your employer extended their hand to you with cash in it, but before you could take it the government took the cash from your employer's hand, took some of it, and allowed you to keep the rest (until you file your taxes, when they might take even more). I don't like the idea of directly taxing someone's income.
If I get a refund, and I get the physical check, I always get a chuckle out of how it is a check from the US Treasury, as if that money was never yours to begin with. That is your own money they are giving you back, and they got to use it interest-free all year long.
Funding the government through a consumption tax is, I think, philosophically a better way to go about this. Gas taxes, for example, pay for the construction/maintenance of the interstates. This essentially is a user fee. The trucking companies for example, who use the interstates more than anyone else, are incurring most of the costs. If you never drive, you don't pay a dime for the interstate. Taxes should be made into user fees to the greatest extent possible.