Sleeping arrangements for baby #1 and 2

When Baby 2 arrives baby 1 will be 26 months old.   We are trying to decide if we want both to share a room in cribs for a while or share a room with baby 1 on a floor mattress. Or should baby 1 have his own room with crib, toddler bed or mattress on the floor.   Any advice would be appreciated. Comments on what has worked or not worked would be appreciated as well. Thank you.