Ok so now I'm actually looking at building a real hackintosh and seeing if it's realistic. From I can tell, the components of the core i3 may be the best to go with are well priced and somewhat easy to obtain.
What I'm really wondering (and my research has yet to uncover) is what does one lose by custom building a mac? I mean, if I use the same components they do, and load Snow Leopard on one using iBoot and Multibeast, am I literally going to get a 1 to 1 representation? Or am I going to have issues with a myriad of things? Like for instance can one use the Apple wireless keyboard?
If I'll lose functionality, I'm not sure it's worth it to bother.
For sure you are going to have a diminished warranty. Yes, each part may be covered by their manufacturer - sometimes for longer than an Apple warranty .... but if there is problem you will need to determine who to call, and then prove to them that is was
their part that failed and not something else. Or the OS. You will have no official support on the OS of course.
It is, in theory, possible to build something that is 100% like a Mac. In practice I believe that there is always something that doesn't quite work right. I base this on reading many posts on these boards from people who say they have built hackintoshes that work "just like a real Mac - - except...." There usually seems to be something that doesn't quite work. Quite often it is something that the user can live with. Other times, not.
You gotta know.... Apple goes to a great deal of trouble to tune the OS for the small range of hardware that it is expecting to work with. And for the combinations that Apple uses. If a brand/type of widget is not used by Apple in any of it's computers, or not used with another bits-n-bob you have decided to use, then the OS will have issues.
While people have had, they say, good experiences with OS X updates, others have not. At anytime Apple may decide to change a bit of the OS that will make it incompatible with your HW choices, or just the combination that you have chosen to use.
Make sure you have good backups. Make sure you can revert to a previous level. Don't rely on the machine for production if you are on tight deadlines, or least don't update anything just before a deadline. (To be fair, I never update my stock Mac if I'm working on deadline either... that is just asking for trouble, regardless.

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We know that the motherboards at least are custom. You can't just go into a store and buy one.
All of that said, I am sure that there are people who are having a wonderful experience running OS X on generic HW. If you enjoy fiddling with the guts of a computer, then please buy a retail copy of OS X and fiddle away and have fun. If you enjoy fiddling then you will have an experience over and above what the average Mac user has. If you want to just turn it on and use it then a hackintosh may not be for you.