The *current* version of Mac OSX does not have that Windows "restore" you are looking for... the OSs' architectures are quite different.
MacOSX has no central/single "registry" file that is modified (when you install an application) that impacts everything whether you want it to or not. The OSX System folder has subdirectories for extensions and preferences and plug-ins and such (as do some of the applicatio-specific folders - it depends how the installer was set up)... these items are called/used only when the application calls or otherwise needs them. If the application is not launched, the extensions and preferences and plug-ins don't get called/used. Typically, if you decide you don't want an application (for whatever reason), just drag it to the trash and empty the trash.
It is possible, over time to have various unused preferences and whatever files build-up from these deleted applications that will never be used. But since they aren't used - and are typically quite small, they are an itty-bitty annoyance more than anything else. Conversely, if you are using an application that (for some odd reason) starts misbehaving, keep the app - but one trouble shooting technique is to trash the specific application's preference file and re-launch the app to re-build that preference file.
There used to be a "Spring Cleaning" app that would go out and hunt down those unused files and make them available for deletion rather than your having to manually identify them, but I don't know too much more than that. *Most* people don't need that...
As far as restoring OSX, just boot from the system discs and follow the prompts... You know - from my postings - that I have been using and supporting Macs and Windows for a while... I do not recall having to "restore" a MacOS based system because of an application installation misbehavior... There were the occasional control panel or extension conflicts, but starting up holding the shift key at power-up allows "safe boot" start-up.
There is a good "MacOSX: The Missing Manual" reference book by David Pogue that has all sorts of information on tips, tricks and other helpful stuff... also, Mac User Groups generally have experienced (and new - and everyone in between) users... Check http://www.apple.com/usergroups to see if there is one in your area. They are not directly supported by Apple and are a good, under-used, resource. For the last 8-10 years (I think), I've worked/presented at a "new Macintosh owner" session held by a Mac User Group in Northern California (and yes, I have been a user group member for that time as well) - I don't know if other MUGs do this...