I also went to UCSD for undergrad and I'm pretty sure I will decide to go to IR/PS this fall. In terms of San Diego/La Jolla, like others have said, you really can't beat the atmosphere and the weather there. On-campus grad housing isn't too expensive, and the most recent one that has been built, Rita Atkinson, is really nice. The only one I personally wouldn't choose to live at, would be Mesa grad housing. Aside from on-campus grad housing, there are plenty of townhouses, apartments, and condos in the area around the school that aren't extremely expensive. When I lived off-campus, it was about 1700 a month for a two bedroom apartment that was actually a nice, and not run-down place. I know my friends that were going to UCLA were in two-bedroom apartments that were about 2000 a month, so I would say that housing around UCSD isn't bad at all. If you live outside of the UTC (University Town Center) area, you can find places in Mira Mesa and Clairemont for even cheaper, and it would be about a 10-15 commute.
In terms of the campus itself, it's a big campus with plenty of trees and great views of the ocean from the higher levels of buildings. IR/PS has its own part of the campus, which is nice because everything is grouped together. I know that there is also an auditorium there where some of the classes are held. Unfortunately due to budget cuts, the IR/PS library was shut down last year, which is a shame because I really enjoyed studying there. It's okay though, because there are still plenty of places to study around campus. There are two libraries that most students like to study in, which are Geisel (main library) and Biomedical Library. I usually went to Geisel because it's basically in the middle of campus, but I would sometimes go to the Biomedical library when I really needed to get work done and study because it's extremely quiet there.
I can't really say much about the faculty as whole, but I did work with one of the IR/PS professors as a student research assistant, and he was extremely helpful, knowledgeable, and accessible. Whenever I went to his office, there seemed to always be students talking to other professors in their offices in the hallways too.
In terms of transportation I agree with orangesplease. It's easy to get around UTC and the surrounding area of UCSD with the free shuttles and city buses. However, getting around San Diego itself with public transportation can be a pain, speaking from experience. Public transportation in San Diego just isn't that great, so a car would be nice to have. However, I'm sure you're bound to meet at least one person that has a car, especially at the graduate level, that you can hangout and carpool with. If you are planning on bringing a car, don't bother driving it to campus because parking permits cost somewhere around $700 for the cheapest permit, and it seems to be going up every year. If you need to commute to campus, it's better to just park your car around a shuttle stop area and take the shuttle to campus.
In terms of things to do and places to eat, San Diego has plenty of things to do. In and around UCSD itself there are a lot of places to eat, but they can be a bit pricey, with the exception of $5 footlongs at Subway and the value menu at Burger King. San Diego in general though, you can find anything from Ethiopian food to Korean food, and nothing can beat Carne Asada fries and Taco Tuesdays in SD. Things to do...I don't really need to say much about beaches, because it's San Diego so there are a lot for you to choose from. Also, if you want some night life, you can either go bar hopping in the Pacific Beach area or explore the bars and clubs in Gaslamp, downtown San Diego. Pacific Beach is about a 10-15 minute drive by car and downtown San Diego is about 15-20 minutes. If you don't have a car, you can find various van/taxi options.
