If you're required to file yourelectronically, don't quibble with the IRS, even if you're more comfortable walking a check to the bank.
Here's a recent example of the potential consequences: An Ohio company made its deposits on time but failed to do so electronically, as required. It didn't trust the electronic process. (In general, companies whose total tax deposits exceed about $200,000 a year must deposit electronically.)
The IRS slapped the company with $174,000 in penalties and the Tax Court agreed, saying failing to file electronically, when required, is the same as failing to file on time. (F.E. Schumacher Company, Inc., 2004-1 USTC 50,166)
Note: For more Lessons from the Tax Court, see page 2.