Well I planned on getting 2 gigs of RAM anyway, just because I'm going to be running data collection programs on the laptop all the time, so I'm going to need it with the extra peripherals I am attaching. (Using some sort of labpro, etc.)

looking at that, you'd probably be better off with a duplicated monitor scenario, since that looks like it'd be a very awkward monitor to work with as a normal everyday-use computer.
however, 1280x800 is a bit of a weird resolution (17" wide), and i've not seen many of them around, usually a laptop based resolution. so that may be a tricky one if you go for a desktop. laptops you'll be able to run a duplicate screen environment, as you've already got your monitor built in, and you just send that same image to the cintiq, and use it in bed.
at the end of the day, you've gotta think of what you want the machine to do. and work around that. if it's power, speed & fast access all the way, then a laptop won't do you any good. however if you're willing to sacrifice a little bit from each of those categories (and lesser storage space) and mobility is your absolute must, then it's a laptop you need.
your options are wide open though =)

Depends how good of a carrying case you'll have for all of this

We use internal HDDs in cases to store media, but we dont travel with them.  You'd have to find a good lightweight drive.  Seagate or Mybook seem to stand out in memory.

I highly doubt you'll ever amass the likes of 40gb in just imagery files, so you dont have to go for an uber expensive huge capacity drive.  You'll always have what's in the laptop or desktop as backup!

Seagate FreeAgent
http://www.newegg.com/Product/Product.aspx?Item=N82E16822148257

Western Digital MyBook (they dont have anything less than 160gb, but the price is similar)
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136173

Western Digital Passport
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136059

Now, for desktop usb storage, the mybook and freeagent are very popular choices, but you'll probably want something dinky...perhaps the size of a passport?!

The passport is also the cheapest for the amount of storage you get.  I think its something worth looking into.

Unless you're after just a handful of gigs, then a 4gb thumb drive will be a cheaper, better option!  Plus, they hang on your keyring, easy storage for....easy storage.