I tend to think that too many system tweak on your primary machine creates instabilities is just a bad idea. However, there are a few basic changes that just make the operating system better. Many of these are available through the judicious use of Onyx. Onyx is an automated system optimization application that also allows you to change some fundamental settings. One of my must changes is the image format type generated by screen captures. The default setting is PNG, but Onyx provides an array of alternative options. I set mine to JPEG as shown below.