I like a small tackle bag. I have tried all sizes, but the reality is you don't need/and can't bring every option in the world with you when you are co-angling. I make my decisions by bringing all the different style lures I can, but limited colors (the ones that work the most). If there is something specific working that day, and you don't have it... odds are your boater will have that and if he really wants to win he will be glad to lend you a spare for the victory.
I have tried many bags, gone big, medium to small... and now absolutely love this bag:
www.academy.com/shop/pdp/h2o-xpress-deluxe-soft-tackle-bag#repChildCatid=312352 This bag has plenty of compartments, the quality is surprisingly good being the H20 Academy brand, and with 5 360 boxes you can fit tons of stuff in there. I also added to small plano containers for my terminal tackle and they still fit inside with the other boxes. You are then left with all the side/front pockets to fill with other stuff.
I also like to compliment it with an add-on, which is an additional bag binder for soft baits that clips onto the bag. I think this is it, but I am not 100%:
[url=www.academy.com/shop/pdp/h2o-xpress-rigging-binder#repChildCatid=517758]
www.academy.com/shop/pdp/h2o-xpress-rigging-binder#repChildCatid=517758[/url]
Trust me, a setup like this is your best bet. You can pack just about anything short of an a-rig, It will be compact and out of the way and every boater will appreciate it.
as for food and drinks... I have a small mini cooler, but as mentioned above... every boater is different. Talk to them beforehand, most will have plenty of room in boat cooler.
hope this helps, I've spent quite some time and money figuring this out. I find this setup is so perfefct that when someone stole my whole setup off the back of a friends boat, I went right back to Academy and bought another one.
cheers