Here's a good tip I just found. Note that this may not be for all cases. In fact, I may have stumbled on a freak coincidence. Here's the story:

I hate java. I hate having java on a server, but hate it even more if it's only for running one small script. Forever, beeets.com has used the YUI compressor to shrink its javascript before deployment. Well, YUI won't run without java, so for the longest time, jre has been installed collecting dust, only to be brushed off and used once in a while during a deployment. This seems like a huge waste of space and resources.

Well, first I tried gcj. Compiling gcj was fairly straightforward, thankfully. After installing, I realized I needed to know a lot more about java in order to compile the YUI compressor with it. I needed knowledge I did not have the long-term need for, nor the will to learn in the first place. I, although revering myself as extremely tenacious, gave up.

I decided to try JSMin. This nifty program is simple, elegant, and it works well. It also has a much worse compression ratio then YUI. However, I trust any site that hosts C code and has no real layout whatsoever. Knowing the compression wasn't as good, I still wanted to see what kind of difference gzipping the files would have.

I recorded the size of the GZipped JS files that used YUI. I then reconfigured the deployment script to use JSMin instead of YUI. I looked at the JS files with JSMin compression:

YUI:
mootools.js     88.7K (29.6K gz)
beeets.js       61.5K (20.5K gz)

JSMin:
mootools.js    106.1K (29.5K gz)
beeets.js       71.0K (17.7K gz)

Huh? GZip is actually more effective on the JS files using JSMin vs YUI! The end result is LESS download time for users.

I don't know if this is a special case, but I was able to derive a somewhat complex formula:

YUI > JSMin
YUI + GZip < JSMin + GZip

Who would have thought. See you in hell, java.