If you like the dock feature Mac OS X has, you might be interested in StarDock ObjectDock. They offer a "plus" version, but I think the free version is good enough. I used it for a while, it gets the job done nicely. On the other hand, I use Windows 7, and I found it to be overkill specially since Windows 7 allows you to pin icons, essentially, a static dock. I recommend it to anyone who does NOT have Windows 7 in their machine or does not like the pinned icons. Compared to the Mac OS X dock, it does NOT have stacks within the dock. A small set back, but not really essential to its overall functionality.
[caption id="" align="aligncenter" width="485" caption="courtesy Google images"]
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Installation is simple. Simply download and install. It has relatively non-technical options to configure . The only option that is maybe a little tricky is the "optimize for performance or memory." Windows 7 and Vista need about 1GB RAM to start off, so if you have less than 2GB, I would recommend optimize for performance. Windows XP is less demanding, but if you have 512MB or less, definitely optimize for performance! Of course, you can always experiment with the setting!
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But if you need another reason to switch to Linux, there is a project called Cairo-Dock which, in my opinion runs circles around the Mac OS X. Above is a screenshot, but if someone wants more information on Cairo-Dock, please let me know!