Windows 7: If you've been overwhelmed by the options and cluttered interfaces of Windows 7-customisation applications, check out GIGATweaker. GIGATweaker sports a clean and easy to use GUI that neatly compartmentalises the tweaks in logical sub-sections for easy customisation.
GIGATweaker breaks up the enormous list of tweaks it assists with into sub-menus for easy browsing. You navigate via the left-hand column and then move through tabs in the right-hand column. It breaks apart the sub-sections so that you rarely end up scrolling through lengthy lists of toggles looking for the entry you want to tweak.
In addition to the well designed GUI, GIGATweaker's "console" feature opens up a text box at the bottom of the application which shows you, in real-time, what GIGATweaker is doing — actions, registry tweaks, etc. You don't need to open the console or even care what it's doing, but if you're curious what it's toggling deep within the registry as you tweak away with it is certainly interesting to watch.
GIGATweaker is freeware, Windows only. Want to check out more Windows 7-tweaking applications? Visit our Hive Five on the topic, Five Best Windows 7 Tweaking Applications. Have a favourite application or individual tweak to share? Let's hear about it in the comments.