There will be a lot of people there to watch LSU, but since it's a home game that crowd should be down a bit. With that said, there will be a lot of people from different schools as well. It's just a great gathering place to watch sports. They've got it all: tons of beer on tap, really good food, and TONs of TVs. The bartenders are cool and if you ask, they'll usually turn 'your game' on a TV near where you're sitting.
Bulldog on Magazine isn't the best place to watch games. Only a few TVs in the bar area and one (maybe two) out of the patio. Bulldog MidCity is a much better option for watching sports, IMO.
Another option is Bruno's - fair amount of TVs, college setting, and the bartenders will change the channel to put it on the game if they don't have it on one already. Debris Fries are a must here.
Edit: I haven't heard of anywhere that people are specifically gathering, but I seem to always see MSU fans at Cooter Brown's when there is a game on.