There are lots of people on this board that will say it is easy and cheap to build your own computer and that buying a Dell (or other prebuilt system) is a mistake. I have no doubt whatsoever that is true for many people, but I can guarantee it is not true for all people.
Let me tell you my story (for entertainment purposes- competent system builders will find it quite funny). Because my frame rate zoomed in on trees can fall to 1 - 2 fps (with detail sliders maxed) I decided to pay big bucks for a new graphics card: $383 (-$50 rebate) for an ATI Radeon All in Wonder X800XT 256MB. Based on published reports this card should be a minimum of about 3 times faster than my old card, a 128MB 9600XT.
I did everything right, supposedly. I uninstalled the old graphics drivers and I did not click on OK when Windows XP "Found New Hardware" tried to install its drivers for the new card. I used the shipped CDROM and that started a multi day nightmare. The CDROM install would hang part way through. After uninstalling and reinstalling, I finally downloaded the latest Cat 5.5 drivers and installed them and downloaded Microsofts' DX9.0c and installed it. None of the multimedia (ie TV tuner etc) features would work- the ATI diagnostics even saying DX wasn't installed properly and that the chip wasn't even a Radeon!
More importantly, my 3D performance in AH, under identical conditions as before, was actually one half as fast! I then uninstalled All in Wonder card and drivers and reinstalled the 9600XT. It's performance was now also one have as fast, and identical to the X800XT. I then did a system restore to before all this pain, and reinstalled the X800XT with the new Cat 5.5 drivers. The performance exactly doubled, but so did the 9600XT- ie I had paid $383 and gone through multiple days of pain to get almost exactly the same performance as I had before. Finally I removed everything, did a system restore again, put the 9600XT back in with its drivers, and installed DX9.0c. Result- slightly better performance than I had before: ie the free download of DX9.0c (upgrading from 9.0b) gave me about 50% better frame rate in certain difficult conditions that I had before.
So the bottom line: I did it myself and I paid $383 to get 1/2 the performance. Was doing it myself cheaper than buying a new Dell? Yes indeed, if I pay myself less than minimum wage for all the time spent on this.
So- don't feel bad about just paying the $200-$500 extra for a prebuilt system. There is a chance you are saving yourself from immense pain.
Now I gotta check Newegg's return policy- after all this pain I may pay them to take it back ;-)
[system info: 2.8GHz P4, Intel D865PERL mobo, 1.5GB 400MHz DDR2 dual channel RAM, Win XP pro]