My credit union. Never had a problem with anything, and they are always friendly, helpful and pleasant. My best CU story; i woke up one night, in a panic, knowing I had a payment coming out taht day, but had forgetten to transfer $$ from savings to checking, so i logged on, but got their additional verificiation notice (I get it sometimes even though i say not necessary on my home computer) and managed to lock myself out of my account.
so i called CS, and while they were not able to reset my online access, CRIVINS! some additional verbal verificaiton she was able to transfer money so my payment was covered. And it was about 3am!
I also have to say American Express. I have 2 cards with them, and their customer service is second to none. Any time I've had an issue its been resolved, quickly, cheeerfuly, professionaly. And if they didn't have an answer then for me, they were able to find out when they might have one. So even though I pay a hefty annuial fee on my one card, i won't switch as they are so good.