I've been through three audits (of businesses) in the past 12 years.
Their purpose is to "uncover the truth", not to hose you needlessly.
You CAN write off a home office, you CAN write of computers, car miles, travel and entertainment, business meals, etc.
As long as these are legitimate business-related expenses you're in the clear.
As a single-employee S-Corp there shouldn't be such an overwhelming amount of documentation and you can probably push through an audit with minimal headaches.
Probably should add the disclaimer that I am not a CPA, follow at your own advice, but man have I spent enough bucks w/CPAs in the last 12 years to hopefully pass on a bit of hard-won knowledge ;)
To my knowledge single employee S-Corps are more and more risky (likely to result in an audit).