One last thing - the IRS has now enacted a simpler provision for home office expense deductions. Before, you had to total up your utilities, real estate taxes, insurance, etc., and then pro-rate it for whatever % of your house your home office is (i.e. your home office is 11% of your total living space, then you deduct 11% of your total home expenses).
Now, (for tax year 2013, filed in 2014), you will be able to simply apply a $/sq ft allowance to make it much simpler if you want. And for mustachians, that would be a huge benefit, since our utilities, insurance, and other expenses would likely be small anyway, so with the flat $/sq ft, you should end up being able to deduct more compared to totaling up your actual expenses.
One other item - don't forget that you can count your home office as your 'headquarters', and ANY trips by car to a client's or work or other business location or any other location qualifies for the generous $.555 mileage deduction. Again, for mustachians, the flat $/mile car deduction is great because our car expenses should be far less than $.555/mile.