Greetings!You may want to check out www.arstechnica.com. It is a US base but they really cover the field on PC configuration, and even give an occasional nod to the Mac side. I have a Mac Performa 630 CD (pre PowerPC), an iMac 350, and my venerable workhorse - an IBM 330 running NT4.0SP6. I also have eight servers running NT4.0 server, Linux and Novell - but they're beyond the scope of your request.
Ready-built vs. piece-built: done both, I loved buying and building from components, but like my stereo system I get tired of tweeking and troubleshooting - especially when the ready builts from HP, Compaq, Dell and gateway are pretty doggone solid.
Also keep in mind that most systems will be shipping with Windows XP installed - convenient in some respects, but pushing the "Big Brother" spectre a little harder than I like. I'm looking at some Linux desktop configs to see if I can wean myself off M/soft.
Hope this helps!
-CLB