I've had countless Makes and models from manufacturer's such as DELL, Alienware(Aurora and AREA-51 models) HP (by the way, I HATE HP) SONY(VAIO series)Compaq, even Emachines.
Nothing stands up to your own custom built computer, ever since I started making my own systems, I have never had a problem.
Personally I would suggest buying all the parts you want and either putting it together yourself or have someone else assemble it.
I still haven't answered your question though, how rude of me.
take a look at these budget systems.