Depending on the needs of internal or external clients, your event may require working with any number of vendors to achieve your goals. But when does a vendor become more like a partner? Is there a point where your contact becomes more valuable to you than just a point of transaction? Of course, the answer to this question varies depending on how critical that service is to the success of the event, and also on how confident you are with that particular aspect as well.
No matter how glitzy (or not) the general session may be, it will take its due share of the planning attention as the pinnacle of conference programming. However, often the unsung hero of delivering content & messaging is the breakout session. With schedules packed between coffee breaks and afternoon rotations, and bookended by even more general sessions, the level of interaction gets higher along with the level of coordination.