You know, some unplanned tweaking in the CSS/JS occurs at the last moment to/after deploy and non-automated minification of your static files really sucks that time. Better we may use some kind of automatic or semi-automatic automation for those repetitive tasks to buy some time.
Something about the other minifiers bothered me that, those were not ready for production usages like elimination of conditional HTML statements (IE hacks!), non-batch, some were only for JS or CSS etc.
Later I found Smaller, I drag and drop my entire template/layout directory and have my contents minified replacing the original, found handy in my case and a recommended app for Mac.
BTW, I found some backward compatibility issue with it and was not being able to use their latest version (1.3.5) in my Snow Leopard 10.6.8. I call for a support, the lead dev Chen Luo promptly responded “Smaller 1.3.5 was built with Xcode 4.4 but Apple removed OS X 10.6 SDK since then”. So, 1.3.4 is working for me and haven’t missed much from 1.3.5.
Disclosure: I have written this review in exchange of a license of “Smaller”.