for programming pretty much any modern laptop will do. you can pick up decent dual core HP's for around $500 or so. try newegg or if you're the type that likes to touch and feel before buying go to Fry's or somewhere similar. Netbooks though will NOT be nice to program on their screens are too small same with keyboards (they are a nice size for everything else but programming on them with the amount of typing would suck). On the Ubuntu issue pretty much anything from a P3 1GHz and up will handle it pretty well so anything you buy now will be just fine. You really don't need a lot of power to program honestly
i agree with overclockingrocks. Any modern laptop is gonna be able to run IDE's such as isual studio or netbeans 6.1.0 and handle the frameworks and languages. Hell, i have seen some pretty terrible laptops working well with C, C++ in visual studio.
If you develop primarily on the laptop (that is you're not going to dock) the most important, in my opinion, is a large, high-resolution screen: 17 inch WUXGA is best, unless you find a WQXGA, which doesn't exist on a laptop that I know of.
Lots of RAM 4GB or more (yes, I'm talking 64-bit OS here) to support whatever development environment you have. And this is where you want to make sure you have discrete graphics such that UMA or SMA or whicherver TLA is being used these days doens't gobble up precious RAM; otherwise, graphics is irrelevant-- unless you're doing THAT kind of development-- which, if you are. then you'll not be wanting to use a notebook anyway or your employer will be buying the machine for you.
CPU is only important if you are compiling. You don't necessarily need multiple cores.
So with that said, I like the Thinkpad W series and the HP EliteBook series, which meet or exceed the above requirements.
HOWEVER. . .
Then there's your budget.
(These recommendations are not taking any student discount into account)
Try looking at the Vostro 1510. Options for WXGA+ and WUXGA, but has shared graphics only.
If you can strecth your budget $150 then the Studio 15 would fit, as well.
Also a fantastically good buy is the HP Pavilion dv7z series for roughly the same price as the Studio 15. It's more geared towards "entertainment (like the Studio series)" but can definitely handle development chores as it can handle up to 8GB ram and has a WSXGA screen option in either glossy or matte (you will want matte)
I "develop" on a ThinkPad T42. Eclipse and Java. I always wish I had more RAM.
I am also a CS student on a budget.
I was looking at the ASUS 1000 HE, with a 10.2" screen and with decent reso, I tries using Eclipse and VS at that reso and diemensions for 2 days and it is pretty ok.
My only concern is that the Atom 1.66 Ghz, can it handle multi-tasking that effectively ?