ExpanDrive
Used by 5 peopleexpandrive.com ↗

“If you watched me work from over my shoulder you would see Mail and a bunch of half-written emails, some finder windows pointing to various servers via ExpanDrive, Safari with several tabs (including Quora, Quora Dev, Twitter and TechMeme), Chrome with several tabs (Quora Dev and YouTube), TextWrangler and Adium with several active threads.”
Rebekah Cox Interview, Product designer (Quora) · via Uses This 
“One app I've come to adore and use a lot is ExpanDrive.”
Maggie McFee Interview, Technologist · via Uses This 
“I use ExpanDrive for all FTP.”
Joe Hewitt Interview, Creator of Firebug, iPhone developer (Facebook) · via Uses This