Aside from software others have mentioned, I find myself using Coda frequently. When I'm working on a variety of different websites via SFTP, and it allows me

Aside from software others have mentioned, I find myself using Coda frequently. When I'm working on a variety of different websites via SFTP, and it allows me to quickly log into a website, make a few changes, hit save and be done. No fiddling with another client or syncing. You can create a preview pane to the right of the code, so when you hit save, it auto-refreshes the website. That's snazz-tastic. For all out quick changes, I haven't found anything that beats it. It has a great CSS editor, too. (If you haven't played with it, give it a serious try. I like to hand-edit CSS, too, but for playing with pixel perfect alignments, it can be quicker.)