1. Bold. Quite simply the most advanced Blackberry ever.
2. 7105t. It's a sentimental favorite of mine. I love the size, shape, feel in my hand, and the screen. It's simple and solid.
3. 8820. I love the 88xx series devices, but I do miss having a camera. Cameras are more useful than I would have thought. Even a crappy one is usable in the right situations.
4. Curve. I had the original 8300 for several years before moving up to the 8800. I eventually ended up with an 8820, which I still have.