I type this on a Dell Inspiron 9300 with 17" Truelife panel, 1Gb RAM and Centrino processor. Its about a year old, but works a treat. Its my third Dell, and I use it every day.
In my day job I buy a lot of Dell and find them to be a good blend of spec, price and after sales support.
Definately go for the 3 year 'Gold' warranty, as the wires on the power supplies get b*ggered after about 18 months of constant packing and unpacking. Also the battery on most laptops only last a couple of years...
Watch Dell's hidden charges - they can charge upto £50 for delivery
Keep an eye out for special offers in the press...