On the other hand 2200 participants made the place quite crowded and it seemed to take away from the informal atmosphere of most theory conference. Since STOC and Electronic Commerce had nearly a complete overlap I jumped back and forth between talks never really feeling fully part of either conference.
For the first time the Complexity conference was not part of FCRC because 2003 is a Europe year for Complexity. In an informal poll I took of STOC people interested in complexity most liked having both conferences at the same place but would rather that happen in isolation, like last year in Montreal, rather than as part of the much larger FCRC meeting.
In what seems to be a trend in CS conferences, wireless internet was made available at the conference site. As you walked around you would pass many people sitting on chairs and on the ground hunched over their laptops disconnected from the conference and connected into another world. Seemed a bit depressing but I too found the net hard to resist--it is always tempting to simply open my laptop and connect, checking email and posting to this weblog.