It's up to you.
I found a desktop to be a huge pain in the ass. This was because if I had a break during classes I could pull out my laptop to do work, whereas that is impossible with a desktop. Sure, I could have gone to a computer lab, but computer labs just aren't the same as your own computer.
And profs definately let you use laptops! Most profs use them themselves!
You can check out the discussion that other students had last year about it here:
http://www.macinsiders.com/showthrea...ghlight=laptop
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McMaster Combined Honours Cultural Studies & Critical Theory and Anthropology: 2008
McMaster Honours English with a minor in Indigenous Studies: 2010
Carleton University Masters of Arts in Canadian Studies: 2012 (expected)
We are people of this generation, bred in at least modest comfort, housed in universities, looking uncomfortably into the world we inherit. -- Port Huron Statement