go with the core2duo (as brainonska said, it has 64-bit processing).
for pixel resolution, i have a 14.1" at 1280x800. i'm a college kid so i don't have any near-sighted vision problems but i still prefer having it at that...1440x900 or whatever the higher one is shouldn't be bad, either.
unless the 7200rpm drive is like $20-30 more, don't do it. i haven't seen my 5400rpm drive slow me down, yet.
depending on your definition of "light gaming" and what games you play, a 7400Go or MR X1400 could cut it.
from what i've seen, 2gb out the door is rarely ever worth it. this one guy wanted to buy a dell from canada and to my surprise dell was offering a free upgrade to 2gb (canada buyers only)..usually it's like a $300 upgrade...plus, i've yet to use all my 1gb, but then again, i don't game.
i'm not a warranty guy so i would get other opinions, but from my experience, unless you go all out on the warranty, it's not worth it.
i would look into lenovo's thinkpad (if the x1400 will suffice for your uses), hp's pavilion line (probably only the dv6000t would do it for you), dell (i would stay away from inspirons...check out the latitude d620 in "Small Business"), and asus (especially if you'll be needing a 7600/7700go or MR X1600/X1700).
i'm not sure about the christmas thing but if you find a good deal before it, go for it. if not, just wait.
EDIT: from the laptops brainonska posted above, i think the cheapest ibuypower is the best one. it comes with a fingerprint reader, too, if that matters. the only concern i have about it is in
this link.
if you look at the second picture from the left, it looks like the screen is wrinkled or something...everything looks real good though