What do you use to store your stuff in?

I thought you already decided against panniers?
1) difficult to swing bike to climb hills
2) carry too much stuff around?
3) no quick access
4) can obstruct movement in tight traffic
5) HTFU

Do you not own a rucksack already?
If so - what do you find the shortcomings are- capacity? gayness? not looking like a cyclist? sweaty back?

Capacity mainly. And I worry about having a backpack any bigger.