Leverage works when the market is going up, but can be fatal when the market corrects. My recommendation for buyers is to make sure you can afford to buy the real estate with enough of a cushion. You may want to take advantage of lower rates, but if you got the maximum loan way back, you may not be able to do so if values in your area have corrected. So, buy good real estate and be careful how far you stretch things financially.
Also, your house is not an ATM machine. Do not buy a new car with your home equity loan. Try to reserve any draws on a home equity loan to things that will add value to your home, like kitchen and bath remodel, room addition, new roof or upgraded heating system.
Time may be running out on tax benefits by purchasing a solar heating system. Talk to your accountant asap if you are considering purchasing one.