Dell have traditionally stuck with Intel processors and as such, you will always pay a premium as compared to an AMD based system.
I note you mentioned DVD's and games. I use a TFT (flat screen) to watch DVD's sometimes and find it perfectly acceptable. Having said that, no TFT is as good as a normal (CRT) monitor for graphics, and particularly for advanced gaming. So if your into that, I would suggest you stay with a conventional monitor. You get a smearing sometimes in fast moving sequences due to the pixel time to change being slower than a CRT, and loose some definition.
AMD are winning the speed war for gaming, and again, if this is a high priority for you, an AMD based system would probably be a better bet and better value for money. You could build (or buy) a high end AMD based system for a similar cost.