I don't know about pricing and hardware quality outside the U.S., but from personal experience I will always be building my own machines. Ever since I learned how I find it to be less problematic and overall more satisfying to build my own. Even if the price is $100 more it's worth it (IMO) to know every piece of hardware that's inside, where it's purchased from and who installed it (me). I get receipts, and warranties if I want, for each piece. The warranties really paid off for two Western Digital drives.

Most of all, I like the flexibility to CHOOSE which pieces I want, and I can buy them whenever I want(when they're on sale). When you get a brandname machine like HP or Dell, you get what they give you. And you usually get small, proprietary designed cases with all the cables packed tightly inside. It's hard to work on them like that. Even if I was interested in a system for M$ Windows and Office I would build my own if for no other reason that to avoid the vendor-specific hardware, drivers and bonus software.

I guess you gotta look at it as an investment:
If you intend on upgrading your PC, either in the near future or about a years time, it would make sense to build it yourself, as you know exactly which components you have, and what you can have.

I know some people though that just buy a premade computer - HP I think. They have the money to spare, and buy a new one every year. Their latest being a 64 bit 3500 Athlon, 1GB RAM, X700 Radeon card, TV tuner card and fancy monitor. Windows XP Pro - or some other fancy media edition I think. But as I mentioned, they have the money to spare, and definetly won't be upgrading anytime soon with those specs. But if they do decide to upgrade, they may have a problem. The case might not have a bay for an additional hard drive, the motherboard will most likely be unbranded and difficult to identify, there might not even be any more IDE busses. Other things might be proprietry, such as the CPU or the way its put in - I know Dell have their own way of doing things there.

So, spend a little extra, and know for sure you won't have any hard time upgrading.
Or have it all pre-built and packaged nicely, and never even think about opening that case.

PS those people I mentioned even spend money to have their PC formatted and OS reinstalled professionally - due to something minor - spyware or virus.

Well on that view it depends. If you look at just how quickly Intel is phasing out CPU sockets and at AGP's death (just TRY to get a good chipset on an AGP card now, yet the most expandable desktop motherboards come with AGP rather than PCI-E), the PCI-E vs. the superior PCI-X race (and it looks like the inferior PCI-E is winning out in the desktop market) and you'll quickly come to the realization that no matter what motherboard you buy right now, it will be obsolete in a year or less. Gone are the days of holding onto a board for two or three CPU and video card upgrades.

You have a very valid point, I am about 1 year and a half on my socket 478/AGP, and am seriously considering the upgrade to 939/PCI-Express.

Beleive it or not, I had the intention of upgrading my CPU to 3.2GHz(currently 2.8GHz) in the life of this motherboard. Now that is very unlikely.

What I did with my computer, I started with 512MB, one hard disk, one CD-RW. Now, I have 3 hard disks, 1GB, and a DVD-ROM (how on earth am I coping without a DVD-RW?)
I also got a 9800 Pro(which still don't work in Linux with HW acceleration) from a 9550, and a Belkin wireless network card PCI, with alot of extra added fans. Would a shop-bought computer be able to handle it all, with its power supply I mean?