Actually I would say it takes way more discipline to live debt-free than to use debt, but that's a personal financial choice.
One point that needs to be clarified is that everyone seems to be using two term interchangeably implying they are the same - Home Equity Loan and Home Equity Line of Credit (HELOC). These ARE NOT equivalent.
HELs are one time lump-sum draw of equity from your home typically with a fixed amortization schedule (term and interest rate fixed).
HELOCs are like credit cards with a fixed credit limit and revolving credit line. Interest rates are VARIABLE on most HELOCs.
The deductibility of your interest can also vary depending on the terms, how much you've borrowed, your AGI and how much current mortgage interest you have to deduct (total mortgage interest deduction is limited to $100,000).