I'm not really interested in the endless "Apple Tax" arguments about Macs being overpriced compared to Windows systems of similar specifications. What I was interested in was the fact that Apple products consistently rank very highly - alongside Asus, who also manufacture parts for Apple, and Toshiba - in terms of reliability and build quality. If I'm going to build a custom system I want to use solid, well built components. So it is worthwhile to research who met the quality standards of a brand ranked high in reliability, right?
Ok, so I don't know exactly which components some of these companies make for Apple, but an afternoon of online research yielded the following list.
Foxconn Electronics / Hon Hai Precision Industry Co., Ltd.
12.1" /13.5" / 14.1: MacBook
Quanta Computer (who also manufacture the OLPC I believe)
Apple LCD displays
Desktops: Seagate or Western Digital
Laptops/Mini: Fujitsu or Seagate
Usually Micron, may also be Samsung or Hynix.
No idea who actually manufactures Apple branded cards, but the chips are either made by Nvidia or ATi and at least one integrated video chip - the Nvidia 320M - was manufactured exclusively for Apple.
And, if you want the same kind of rock-solid UNIX-based operating system too? How 'bout another UNIX-based OS for FREE! Mac OS X was based on parts of FreeBSD and NetBSD combined into Darwin, which forms the UNIX underpinnings of OS X. You could either install a FreeBSD or NetBSD or you can actually get Darwin for free as well. This doesn't give you Mac OS, though, as a lot of what comprises Mac OS is in a higher-level, proprietary layer used and required by "Mac Native" applications to work, so you can't run Mac native software on Darwin. What you CAN do, though, is run thousands of UNIX and Linux programs, and you can install a GUI desktop environment like Gnome or KDE and "theme" it to look just like Mac OS X, and install AWN Dock which works just like the one in OS X.
If BSD or Darwin are too intimidating, get a Linux distribution since they often have "Live" discs that let you try before you install, and have nice installation wizards when you've found one you like. Whichever UNIX or Linux you choose, you can also use a compatibility layer called "WINE" to run many (but not all) Windows programs - without having to have Windows installed. For many users a BSD or Linux install will meet their needs as well as Windows or Mac OS - especially if most of what you do is surf the web, e-mail, chat, watch videos, use an office software suite there is no reason to be spending money on an operating system or software to do those things. It's only when you need to use professional applications (such as Adobe Creative Suite or Final Cut Pro) that you NEED to have a commercial operating system capable of running them.