Well, if you are in Computer Science, even in first year, a laptop is REALLY handy.
First, you have access to a computer 24/7. In my school, the campus is WiFi enabled and you can browse the internet to check sites/email/etc.
Second, in CS, the profs in my school uses a script for students to hand in their assignments. CS courses have computer labs (Solaris, Linux, WinXP)which require you to use computers (duh) and you are able to work ahead to save time if you have a laptop.
Third, with a laptop, you can have exclusive access to a computer (that is, if you share your desktop with others such as family members). In CS, they have you install SDKs and other apps to use for an assignment. More specifically, you will need a customized computer that has stuff like Java, C/C++, GNU/Linux (or run cygwin), Eclipse, etc. If you have your own environment setup and you can take it on/off campus, a laptop will help you work on your assignments.
Also, schools have deals with Microsoft (MSDNAA) and you can obtain Windows, OneNote, Visio, etc. if you are in "high tech" programs like CS, ECE, EE.
Finally, you can do the other stuff other posters are talking about like viewing pdfs, powerpoints, etc.