I would get the 24" - the more screen space the better! And the panel is a higher quality anyway with wider viewing angles and its just overall better looking.
Getting a bigger panel also means you can just get a USB TV tuner and get TV on your mac. 24" is a good size to watch TV on, including high-def TV which is available in most areas now.
Saves space compared to having a separate TV and it also means you can watch some of your favorite shows if your roommates/housemates decide to be jerks and watch TV or use the commons area while your shows are on. (Assuming you'll be living on campus).
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The whole idea of having a laptop for college is ridiculous and I have no idea how this whole myth of "laptops are better for college" got started. You don't need it, plain and simple.
You can take notes with a pen and paper just fine and unless you are attending some experimental school or lab school chances are your professors will not require it.
Using a laptop during a lecture is just distracting and pointless.
From what I saw in my 4 years of undergrad and 1 year of grad school most people with laptops keep them on their desks at home and hardly ever bring them to school (defies the purpose of buying a laptop).
The few people who bring it to class use it to follow along with the PowerPoints -- something the rest of the students without laptops do by printing out the slides and taking notes on them.
Laptops are also more likely to be stolen (break into a dorm room, stuff it in your backpack and leave unnoticed compared to being seen walking out with a GIANT, HEAVY computer. Laptops are the most commonly stolen items on campus next to digital cameras).
Laptops are also more fragile by their mobile nature, you are more likely to sit on your laptop on accident or drop it, or have something spill on it (since the computer base right there on the desk), where as with an iMac the base is elevated enough so that spills don't get anywhere near the electronics, and you will definitely not be sitting on dropping your iMac on accident.
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In the case of the iMac, it takes up very little space relative to PC desktops or non-all-in-ones, looks great, performs great, can run Windows for compatibility reasons, and can double as a TV/DVD watching platform (much better to watch TV and DVDs on a 20 or 24 inch screen rather than a 13 or 15 inch one). By knocking out two birds with one stone (PC & TV/DVD) you also save a crap load of space which is important because space is scarce in cramped college life. The perfect COLLEGE computer.
Recommendation: 24 inch iMac with a TV tuner for dorm/college life. Recommendation also applies if living at home.
I would further recommend looking into buying an iMac through Amazon or another retailer online because depending on your area the savings you get from a student discount can be negated by the sales tax.
In other words, it may be cheaper just to buy it at full price with no shipping or taxes than buy with the student discount and pay sales tax.
