Often times I am working on a web server and I am not sure which files need uploading. I use a utility to compare files to see what changes I’ve made, but never over FTP. Well, in Mac OS X, you can mount an FTP server, just like you would mount a SMB server. After mounting your FTP server, you can browse the file structure in Finder and use your file compare utility easily. I recommend Beyond Compare for file comparison, but they don’t support Mac. I use File Merge instead. It is better than nothing, but pales in comparison to Beyond Compare.