amd turion or pentium processor is best, not a celeron although a sempron if you're on a tight budget is ok.
graphics wise try and get ati or nvidia. watch out for 128mb dedicated graphics processor because if it's reluctant to tell you what it is, it'll be intel.
be sure to go and look at the screens of the laptops in a shop of the same family you want to buy, some companies have much nicer screens than others, dell screens have a really poor viewing angle for example.
do the same for touchpads, i hate the dell ones personally but it's down to personal taste.
ram 512mb at least, you can get nice big hard disks too now. try and find a sata one if you can although i think it's just the 80GB+ drives that are sata.
graphics again just a reminder about the cababilities of the different models
ati radeon X300, X600 etc shader model 2 (2.1?) bigger the number the better, check the ram too
radeon X1400 etc are shader model 3, again check the ram though
nvidia 5x00 etc shader model 2
nvidea 6x00 and 7x00 are shader model 3, but don't do hdr and fsaa at the same time (like a laptop would do that anyway
)
beware these nvidia numbers 6800 is better than 7300 but in a laptop just try to get a big numbered ati or nvidia basically
i think that's everything.. oh check what ports it has too
good luck finding a nice one
AMD athlon 64 3000+, 1GB ddr400, 400GB total hdd, ati radeon x700pro 256mb (pci-e) 17" tft(@1280x1024).