Cocktail: Swig your Mac into Shape
Cocktail, simply put, is an easy way to tweak your mac to attain its optimum performance. It uses unix commands to change things that in most cases you couldn’t do without the command line. It can do jobs such as clearing caches for your system, by user or browser and of-course, which can be selected individually. Pilot is the scheduler portion of Cocktail which lets you clean your system on action script to make sure that it gets done regularly and efficiently.
Ever wanted to view logs from an installation of a specific application? Cocktail lets you view, rotate, delete, and save logs to different locations. You can modify sleeping profiles that you have on your mac. You can create symbolic links to another disk and also lock files. You can tweak your network to some really geeky settings like speed, duplex and MTU. Find the .DS folders really annoying? Cocktail can delete them for you. What I liked best about Cocktail is it allows for customizing Exposé and can reveal some hidden settings of Mail, Safari and other applications. There really is a lot it can do, for a full list please see their website. Cocktail is priced to move at just $14.95.

Nice feature set, but i use Onyx.
[...] dock is attached to the top of the screen and not the bottom, left or right. I achieved this using Cocktail, and I know other apps like MacPilot can do the same. If you know any others, or free alternatives, [...]