Get a Vostro model if you go with dell (small business line) with an upgraded battery (or a dual battery). 15in if you want portable, 17in if you mess with big pics.
I was not a dell fan until recently. They went through a shitty phase which seems to have gone away with their acquisition of alienware a few years ago. Last I checked, the vostro line was the best model to get for a budget. It has the hardware quality of XPS laptops with the simple looks of a business laptop (and a price to match).
I own a vostro 17in model, and have for a little over a year. It has 2GB of ram (you'll want 4) and plenty of drive space. The card is top of the line for when I bought it (8600M GT) and the CPU is no slouch (T7300). The machine plays crysis fairly well, and even better if you overclock the card a little.
On the ram, if you buy 2GB (which is probably standard) then you might find matching ram at a better price at
Dell Computer Memory, IBM, Lenovo - identify RAM DDR DDR2 DDR3 . They will match your model via drop-down menu and get you ram that works. I have years of experience with them, and especially for OEM machines where timings aren't configurable, the ram they offer is a perfect match. After you get a 4GB kit, you can sell the old ram and make some money back, too
. Otherwise, get the 4GB from dell when/if you buy it.
Mine comes with a card reader built in. I imagine the 15in models do too.