Completely depends on your financial situation and tax bracket. Sounds like you already have security, I'm willing to bet you don't have a ton of assets. Please don't take this as a personal assualt but being as responsible as you have been with money, I am sure you could have been ten times further (as far as net worth) if you would have used the money you've made in different ways.
Leveraging - it's how the banks make money. Borrow money at a low interest rate and lend it at a higher interest rate. For instance, that 7-8% that you'd be paying on a home equity loan...
If you where to take 100k from the equity in your home, borrowed at 8% interest only payments would come to 667.00/mo
Now put that 100k into an equity fund (such as the russel 3000) and get at least a 10% return on your money (russel 3000 average 14.9 over previous 10yrs) compounded annually and look what happens
1st year return = $10,000.00
2nd yr return = $21,000.00
3rd yr return = $33,100.00
4th yr return = $46,410.00
5th yr return = $61,051.00
6th yr return = $77,606.00
7th yr return = $95,366.00
8th yr return = $114,902.00
9th yr return = $136,392.00
10th yr return = $160,031.00
Total amount in fund at end of 10yrs = $260,031.00
Total spent on payments to home equity line = $80,040.00
Total profit = $79,991.00 / We'll call it 80k return for doing nothing, this is not taking into account your tax benefit either.
Make interest your friend, not your enemy.
Now as far as the home improvements... That's completely on you but I wouldn't finance home improvements, I would pay cash for anything that is not "necessary to sustain life". Financing unecessary things is why americans are in debt.
Speak to a qualified financial advisor.