LG VX3200
I could be surrounded by people on VZW, all talking on their cells, no one dropping calls and I couldn't even dial a number because I had no service. Had it replaced several times, given several excuses why that particular unit had issues, and had several unhappy years of cell phone usage (I didn't know that I could buy a new phone in the middle of my contract, I thought I had to wait until my contract was up to change phones
)
I got better reception with my Nokia 5130, although, I was on Cingular at the time...but still!