Panic software has just released Transmit 4.0, an upgrade to the staple of FTP/File transfer apps for the Mac. It supposes ftp, sftp, amazon s3, webdav and more, plus all sorts of speed increases and sexy UI tweaks. Be sure you read through the (very nice and ajaxy) webpage, but don't miss the "one more thing" at the bottom which might just push me over the edge to buy this right now.