My friend just called two days ago. He was following Irwin Shiff who teaches people to file an empty form with just a signature because he claimed that the constitution doesn't allow federal taxes on income.
Well, Irwin is in Jail now.
My friend didn't file right in 2006 and 2007. He as on $250k salary both those years, but stopped all federal withholding from his paychecks. This year he started his own business and grosses $100k per month.
Two days ago he called to ask for my help. The IRS sent him a certified "intent to lien" on his bank accounts. He immediately got online to move money around and they had zero'd out all his accounts including the ones for his two corporations. He has over $100k in checks outstanding right now.
I don't know how much they took, but they wiped him out in one day.
Filing is a pain, but it could be worse.