I want to get a new filter for my 100 gallon, and right now I have three whisper filters. What would be my best filter for a 100 gallon with 7 goldfish in it??

Hi and welcome to the site. WOW a 100 gal tank, I bet it is gorgeous!!

With gf it is best to run a filter or filters that do 10 times the gals an hour. So you would want filtration to be around 1000 gals an hour.
I would think a canister may be beneficial at this point, I don't have one but my husband wants to get one if and when we upgrade to a 100 gal tank.
I have heard good things about them.
Obviously a filter that has biowheels are great as well. They help you to keep the cycle in place in doing major water changes or cleanings of your tank.

Good luck on your search and post some pics of that tank!!

ya u will need a canister filter
sum brands are Fluval, Rena, EHEIM....