I have about a dozen Sox caps in my closet. I used to love the fitted caps, but I've found they shrink and stain after so many times being worn to the park. My '59 Sox American Needle and '05 World Series hat fit a bit more snuggly than they used to, so they don't get as much wear. I bought a low-crown fitted 5950 in 2010, and that's never recovered from the sweat stains incurred on Frank Thomas Tribute Day when I sat in the upper left field corner.
Top three right now are the 2003-2006 BP hat, the '47 Twins diamond-sox cap, and the '47 Twins white panel/sox logo cap. All three caps I've rinsed off with soap and water at various points, and they always come out feeling and looking great. The '47 Twins hats are moving up the list. There are a couple more I'd like to pick up someday, but Lids.com seems to be out of certain sizes.