Best in relative terms, it’s quality, reliability etc. Obviously you cannot compare a modern Smartphone and a 1990s Motorola directly.
My choice? Nokia 3310. Stylish. Rugged. Long battery life. It’s like the DC3 of mobiles.
Plus I spent lots of happy hours learning through texting on this phone that girls do have dirty minds and playing Snake. Teenage years are in retrospect quite nice. :D;)
It fit nicely into a pocket or small purse, it was just all-around awesome. I loved that phone, it was the first phone I had with a decent camera and I could text reasonably well on the numeric keyboard. It was also very stylish and PINK!
The phone after that was one that had the flippy keyboard so texting was easier, and then I upgraded to an iPhone. I just got an iPhone 5C. In pink.