| I know from my university career that the laptops do come in very handy, but you end up spending lots of time worrying that someone is going to walk off with your shiny new $1'000-2'000 laptop. I've seen tons of laptop bags sitting outside exam halls and I know of more than a few that walked off (including out of libraries, cafeterias, etc).
My personal preference is to have a powerful desktop and an older/used laptop. Most colleges have lots of computers on campus that can be used if you need the extra power there.
My over-exaggeration on laptops is that they have about half the performance of a similar desktop for twice the price. I know it's not quite true... but with all the features that limit power consumption (when running off batteries) and heat production it restricts what a laptop is capable of. IMHO Mobile video cards are really bad for this, but hard drives and other components are affected to a lesser extent. The current high end parts are not available in laptops, in a laptop you usually get ~DDR2-533, 5'400 rpm drives, mobile video cards, but for the same money a desktop will use DDR2-800 or 1066, 7'200/10'000RPM drives and a much more powerful video card.
You could put together a somewhat older but very nice dual core AMD desktop for ~$1K (or less if you go with the generic parts or buy at $big_box) and pick up a late P4 or early Pentium M (or AMD equivalent) era laptop for ~$300-400.
While you might have to pony up an extra couple hundred to get both a desktop and laptop (depending on what you want)… it also gives you some redundancy, if something goes wrong with either machine – you have a backup and an easy way to get online to help troubleshooting/download drivers/rant/etc
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