hey j-met. I actually brought both my PC into residence and my laptop, so hopefully I can help give some advice. In terms of having a PC, i wanted it so I can listen to music and watch movies like chad said. However, sometimes for some classes, the professors do speak really quickly and I find copying notes by hand not fast enough, so laptop is nice. I like the convinence of being able to bring my laptop to the library to study or to use for group projects and presentations in class.
In terms of running both computers at once.. It would start getting a bit heavy load for the electricity.
Also, it might start getting a bit warm, depending on the room and if you have a roommate/fridges, etc. Also, the other concern would be desk space. Some residence, the desks are not that big to fit alot of stuff. If you want to put your monitor, keyboard, laptop, and books, it might get pretty crammed up. I think in regards to desk space, see where you get in to residence and the size of the table. Look at pictures online and check them out to see if you even have enough room to put both. I think that would be the biggest concern for bringing both. I lived in Les Prince and Keyes, so the desk was big enough and I could put both up. However, desks in Brandon for example, would be difficult to do that. So wait and see when you get your residence choice!
But in general, having both was nice.
Sometimes annoying to transfer files though between the two, but that's alright.. also i tried dual screen for a while, it was pretty nice. w/ my laptop and monitor. that can be an option as well.
hope that helps!