I do most of my day-to-day banking through WaMu, since it's free, they have good service, enough ATMs around, etc... but I carry a pretty small balance there (float only around ~2 months of expenses). I have enough reserve cash in non-WaMu savings accounts to cover ~6 months of essential expenses at zero income. So it would be a hassle if they went under, but not a life-breaker for me.

I'm more concerned about my 401K, to be honest.