I'm looking to revamp my whole tack room and was wondering what saddle pads everyone loves. I've seen so much from Five Stars, CSI, Best Ever, Professional Choice, Inpact gel. Which brand does everyone love? 

My experiences:

5 Star is by far my favorite.  That is all I currently ride.  They really last and they are American made.  They have the highest percentage of virigin wool of any pad and wick heat/moisture away from the back.  They can also make you custom shims if you are having a fit issue that velcro to your pad.

You didn't mention this brand, but Tod Slone is my #2.  IMO they are second in quality to 5 Star.

Best Ever--I've had three different ones and they compressed VERY quickly.  They don't seem to have as much "structure" as a 5 Star or Slone. 

CSI--not a fan unless you are having saddle fit/back issues.  I had one horse/saddle combo that I loved it on.  Did not like on anything else.  Rolled badly on the rest of my horses of various wither/back types.  They do hold their value well and I recouped my money when I sold the pad after I sold the horse.

Impact Gel--not a fan.  Per my chiropractor, the gel holds heat on the back.  I know several people that like them though.  You have to watch for the gel to harden.

Saddlright--I've never personally had one but I've heard nothing but good things from friends who do.  If I ever feel the need to try something besides my 5 Stars this would be the first one I would try.

5 Star is the only thing I will use.

Five Star is my number one, they are so much softer and they don't compress like some others.

My second favorite is Todd Slone pads.  I've ridden them for many years and they hold up great.

I think that depends on the horse, the saddle you ride and how your saddle fits as well as the conformation of your horse. 

I use  contoured wool pads by Weaver Leather on all my horses. They work well.

Are pads for the tack room or for the horses? My answer depends on your answer.

5 star is all that I will use now

I used to use all 5 stars, until they created multiple hard bumps on my horses spine that I had to get lasered off. They are just too soft for my guy. I switched to CSI years ago and will not buy anything else. They still look new even after a couple years. They never slide or shift. Very well made pads.