Go with an HP product. HP builts better products than Dell. There is innovation in a HP product. Dell just buys whatever is cheaper in mass quantity and puts it together.
If you want something with a 17" screen the go with the HP NX9420. Its new and just hit the market. Has all the bells and whistles and the latest technology.n Duo Processors and much more. I seen it and actually have it beside me giving it a little test drive. Very slick machine.
Otherwise, I own a NC8230, 15.4" wide screen and just a excellent built machine. Owned it for 5 months and love it. All the options. It was pulled off my desk by my german shephard one evening and still working fine. Its also backed with a 3 year warranty!
Either way you go, get the extended warranty (3 years) and think about the accidental warranty just in case it falls or if you decide to put your fist through your screen!