My first was the Universal Waite. In the beginning, I wasn't very sure if this deck was going to "work" for me; the people looked flat and stiff, and nothing really spoke to me. After trying to work through the LWB, I became even more frustrated with it. It was over my head, and nothing made sense, and I was in a panic.
But one day, I just pulled out the cards one by one, and I asked myself "What does this image say to me?" From then on, it clicked. I took a more intuitive approach to it, and it all seemed to snowball, in a good way.
I've moved on since then, but I still have the deck, and I still work with it sometimes when I'm stuck and just feeling like nothing's clicking.