Are you thinking about borrowing from your 401k plan to help you ride through a rough patch? I've done it and it was not a good idea.
Sure, you pay yourself back, plus interest, but the loan interest rarely matches the investment performance of the 401k plan. And there are other arguments: administrative loan fees and the double-dipping repayment schedule: OUCH!
Borrowing from a 401K plan is just one of the 10 mistakes listed by Bankrate.com from this feature on MSN.
The list of don'ts includes: home equity loans, saving money in your kid's name and falling for store-branded credit card gimmicks, such as shopping discounts for opening new accounts.