I know the Akubra Fed IV has always been extremely popular, and is extremely durable hat. It's made by Akubra, and has often been supplied by David Morgan. I don't see it listed on their site at the moment, but if you can track one down that's one option.
You can also buy the original Herbert Johnson Poet direct from them in either rabbit for about $500 USD or in beaver for about $700 USD (pretty steep, but consider that HJ is THE premier hattery of the UK). I bought an older '90s model, pre-original block discovery (the original hat block that the Poet was shaped on had been lost for a few decades and has only recently rediscovered) for about $250 USD on eBay and it gets the job done for me.
Adventurebilt is another great choice. I believe they were the original supplier for the KOTCS hat.
Anyone know the quality on these?
LEIFUR Lucky FEDORA by HUFVUD The ultimate adventure hat that makes an archeaologists look sharp in the most dire of situations. This style of hat is made to look more boxy and bulky on the top crown for the classic adventure shape. Finished with a Grosgrain Ribbon, Cotton/Rayon blend and a silk l
www.hufvud.com
Never bought one, or seen reviews on them, but I've always admired the look.
Coyle's Downtowner has been mentioned, but also pointed out that it's been out of stock for a while. I have one and find the brim to be a tad misshapen, and the felt is extremely thick making it a nice and warm winter fedora, but not very useful for cosplay purposes, or summer wear.
Penman is a great hatter, but I've always found his Indy hat brims to be over curled.
Just keep in mind that tretty much any hat worth its weight will run you over $100. Never buy wool for a fedora, it's stiff and uncomfortable, and doesn't last as well as beaver or rabbit felt.