*if you use tech bargains and dell.com you can get the absolute cheapest deals possible on intels (on a good day/deal/overstock rummaging run)...
*your nearby stores (best buy compusa ssircuit city, but especially office depot for some reason) have weekly sales and 500-750$ laptops are offered every month or two (amd 64, radeon gfx, 15" usually 512mb ram and 60+gb HD) which are the best overall value...
*for everyday prices, newegg and sometimes powernotebooks (more for high end) are pretty good
8lb may be a bit heavy to set on your lap, but if you've always got a table it's not too bad (17" is nice), its more of a desktop replacement than a laptop though

the biggest cost is screen resolution in laptops, most only have XGA by default configs (1280x960 on a 15.4" which was more than enough for me).
I'd advise against tablets though... my dad's owned three now (from his work) and they tend to use slower processors, but besides that its a lot of extra cost for very very little in features... the handwriting stuff still isnt that great so you'll be going over it all with your keyboard (correcting it) anyways (most people type faster than write to begin with though, which is why i never really saw the point).
For my money, you can't beat the amd 64s, super fast, super cheap.
hope that helps.