If at all possible, paying off the HELOC and closing that account can help speed up the sale of the home by not having any other lien on your property except for the principle lien.
Hope that helps.
This is truley personal preference and a point could be made on either side.
The bottom line is to you want the money in your pocket now or at closing?
The more you pay toward liens on the property the more money you will receive at close of escrow of the home.
Depending on the location and marketability of your property it may or may not benefit you to continue to pay excess toward your HELOC.