After reading the last few posts, I wish i could say: go ahead, get my Dell! (OK, I know it was lame...)
But I can't!
There is no way he can fit his Video Card in the Dell or HP case. And even if he somehow manages to accomplish that, it will be like in an oven in that little space.
I had to re-package my HP into a larger case in order to fit all the components properly, and have some room for extra fans, Hard Drives etc. And it was the only way to keep the temperatures down, too.
As soon as he does that with Dell or HP, he loses his warranty.
And he will need a new Power Supply. HP or Dell usually supply very generic PS', just to satisfy current power requirements. My HP was only 250W - enough for GeForce 440 8x AGP, but way too inadequate for BFG 6800NU that I have upgraded to. And I punched a hole in the side of the case to make room for an extra fan to cool the CPU.
But when I tried to fit the BFG 7800GT, it was SO tight that I can't believe I did it. And it was HOT.
If he decides to go with Dell, he should make sure that he orders the Video Card, 2GB memory and all the options from them, so they can properly take care of the Power/Ventilation issues. This way he will get to keep the 1 year warranty, too.