You want a high end dell? Have you ever priced a replacement board from dell? Dell frequently charges $200 or more, and stops carrying the board after only 12-18 months. I have worked at dell manufacturing in austin several times. The low end pc's aren't a bad deal, but the high end stuff is too expensive. If you want a gaming system, I would learn how to build it yourself. If you live near frys like me, then the combos will often give you the motherboard for $20 or less with the cpu.
If you really want a dell, buy it at the end of their quarter. The next end of quarter will be in July. Check the power supply specs carefully before selecting a video card. You may do better buying that separately and installing it yourself. Dell makes large profits on upgrades. Just check the dell power supply and be sure it includes the cables you need, usually a 6 or 8 pin connector for mid to high end graphics cards. Newegg has some good deals on graphics cards, better than dell or frys.