I always like LAN support because it means me and a bunch of friends can get together and play for fun while drinking a few beers. It's a social event too. We currently play CoD:BO because BFBC2 doesn't support LAN. Unfortunately, BF3 will not support LAN either, so we are currently stuck with BO. We've done the other CoDs to death and are looking for something new, so for us, MW3 could be just the thing. We don't play MW2 because some of us (including me) boycotted it because of no dedicated servers.
I don't think LAN support is for competitive play only. It's for guys who like to have fun too