Borrowing money to pay off debt

War On Credit Cards posted a discussion about whether you should borrow money to pay off debt. They are in support of it if you can get reduced rates on your debt and I agree with some of their points. The biggest concerns I have are when people do the following:

1. Trade unsecured debt for secured debt by using money from a HELOC to pay off credit cards. There are advantages and disadvantages to this, the main being: you get a lower rate but you potentially put your house on the line. My biggest concern with this method is, if you haven't learned your lesson, you can put the debt on your HELOC and then you run up your credit cards again compounding your problem. There's also the problem of, if you hit a financial rough spot and can't pay your HELOC payment, with credit cards they just trash your credit but with a HELOC they can take your house. It can be dangerous so keep that in mind.
2. Borrow money from a 401(k) or 403(b). It sounds like a great idea because you're paying interest (at a low rate) to yourself. However there are some dangers. First, if you lose your job, most likely your loan is due within 60 days and if you can't pay it, it's considered a taxable distribution and you have to pay taxes and penalties. Second, many times if you have an active loan you can't make additional contributions. This may mean that you miss out on employer match. It definitely means that you miss out on the ability to contribute (you can't replace missed contributions) which can drastically reduce the money you have in retirement since you also lose all of those earnings. Third, as in the second example, when the money is out of your account for the loan it isn't earning for you and you can never replace the benefits of those compounded earnings which could have a much larger impact on your financial future than carrying credit card debt.

So, basically, if you're borrowing money from credit cards or prosper or something similar in order to get a lower rate then go for it. However, if you're borrowing from your house or retirement, please, think long and hard because if something happens you can really do serious damage to your financial future.