It depends.
I think the most I ever carried was as a travelling DM for D&D -- about a dozen books for any given session. Plus dice, screens, and a large filing box full of campaign notes.
In our current campaign we play at the DM's house. He's got about 6 binders of campaign notes; a dozen rulebooks; dice; minis; yada yada yada.
As a player I've rarely brought more than the rulebook + dice + character sheet. I think the only exception was a WEG Star Wars campaign, and that was only because the GM wanted access to my Star Wars supplements.
I think the most I ever carried was as a travelling DM for D&D -- about a dozen books for any given session. Plus dice, screens, and a large filing box full of campaign notes.
In our current campaign we play at the DM's house. He's got about 6 binders of campaign notes; a dozen rulebooks; dice; minis; yada yada yada.
As a player I've rarely brought more than the rulebook + dice + character sheet. I think the only exception was a WEG Star Wars campaign, and that was only because the GM wanted access to my Star Wars supplements.