I've seen several libraries at several different campuses, and I must say, I'm in favor of Lied Library. They have everything you need to handle all of your student needs. Scanners, media rooms/computers, there are desktops on every floor; you can also borrow headphones and laptops. They even recently added dual monitor computers for increased productivity, which I have familiarized myself with recently.
There is a Coffee Bean and Tea Leaf for those much-needed coffee breaks, along with overpriced snacks, and bathrooms on every floor. There are also plenty of study rooms for group work.
Only thing that would make it slightly better is to have it operating 24 hours during the school year, but I suppose you can't get it all. Great place to study, I've had many productive hours here; I'm surprised they haven't started charging me rent yet.