@ zakhal: Why do you say Dell is a money waster? Bundled software? Pre-designed? Or what? I've had five Dells over the years and had no problems ever(except that wonky nvidia graphics card which they replaced for free)
Granted, you used to have a lot more leeway in picking out your components, but you still can go to their "Gamers Only" page and build your own XPS. For those of us who aren't expert enough to build from scratch,of the premade variety, is there a reason that Dell is worse than say, Hewlett-Packard?
I think that out of the large system builders Dell is actually one of the better ones. Personally, I would always prefer to build myself or to get a custom PC from a local retailer but if you have to or want to buy from the likes of Dell, HP, Acer, Lenovo (formerly IBM), Toshiba etc then I guess that Dell is an excellent choice.
The disadvantage to custom built systems is that Dell is very often using Intel OEM mainboards for example. These mainboards are not very well supported (some other manufacturers like e.g. Asus deliver BIOS updates for boards that are several years(!) old) and you will often run into restrictions when you're trying to upgrade a system based on an Intel board.
Same goes for the PSU. It is often tailored to power that exact system configuration with only very little tolerance for a heavier drain so there is some potential that you might run into power issues when upgrading.
It can even happen sometimes that the case is not 100% standard ATX and that you can't use certain other 3rd party components/replacements with the system than those that originally came with the computer.
It depends on the individual system and series but those are basically the issues you could at least theoretically encounter when buying a Dell since those are rather typical problems of systems that are made by the large OEMs.
If you just want to buy a decent system though that suits your needs perfectly and if you never want to touch it again (upgrade etc) then a Dell, HP, Acer, whatever can be the perfect choice, of course. You will usually get a very good, high quality system from these manufacturers. Service and support is expensive so it's only in their own best interest to ship a good and stable system to you. And you can be pretty sure of that since they have very strict testing criteria for new systems. These systems aren't inherently bad. They are usually great "as is". The problems can arise when/if you want to change or upgrade stuff but if you aren't into that at all then you'd probably never even notice the restrictions that come with a Dell or any other OEM's system.