I just returned from a trip to the University of Illinois, Urbana-Champaign. I brought some items with me that turned out to be very useful so I thought I'd pass along the tips in case you are in the market for such items.
Headphones - I brought several pairs along, but I really enjoyed my Sennheiser HD 280 Pros. They are full-size headphones, not earbuds or anything. This gives them much better sound than most smaller headphones. They also provide a lot of sound isolation. They are not actively noise canceling, but keep out most external noise due to their design. What makes these better than most full-size headphones is that the earpieces both pivot so that they are aligned with the body of the headpiece. This allows them to be stored in 1 1/2-2" of space rather than the 4-inches or so that would be required of other headphones.
Jacket - I wore my Scottevest Evolution jacket. This jacket has 15 functional pockets (and several other smaller ones) which makes it great for packing things. Instead of trying to put a backpack or laptop back under the seat, I just put all the items I want for a plane flight into my jacket which stows easily and still leaves room for my feet to move. There is a pocket perfectly sized for a paperback book, one just right for a magazine (in the back), one that perfectly fits my Eee PC (below), space for a water bottle, plus pockets for Zune, phone, etc. In addition, the arms come off turning it quickly into a vest. I found the full jacket a bit warm for most airports and airplanes, but the vest to be quite comfortable. The arm pieces stow easily in the back pocket and attach quickly when you are ready to leave the airport and face the elements.
Laptop - I brought along my Asus Eee 1000h on the trip. It has several benefits over the Lenovo and Dell laptops I have brought on previous trips. First, it is very light. It weight around 3 lbs which is a lot nicer to lug through an airport than the 6+ lb notebooks I was accustomed to. Second, the battery life is amazing. I'm currently looking at 75% of my battery left and an estimated 5 hours, 27 minutes of time remaining. The time drops when doing more than reading papers and typing blog posts, but it is still very respectable. The third advantage is the size. The 1000h is big enough to have a functional keyboard, but small enough that it is easy to stow in a backpack or even the inside pocket of my Evolution jacket. It's also small enough to comfortably open in a coach airplane seat. A 15" laptop can't fully open in those cramped quarters. The problem gets even worse if the person in front of you decides to recline. The 1000h suffers from no such problem.
[Updated SEV link - Thanks Bill]