Now I have 3 hamsters, I am amazed how different they are. They are all different colours, of course, but they all have completely different personalities. My latest addition, Fuzzy, which I think is a boy has only been with us since Thursday but he is an absolutely manic hamster. He has so much energy I can't believe it. He is very friendly and I can hold him and play with him but he loves to run and climb. He spends ages in his ball. I put him back in his cage but he is immediately hanging off the bars begging to come out again. He is also a bar chewer and gymnast, he climbs all over his cage like a monkey. He runs on his wheel really fast for hours and hours.
My other new hamster, now called Sid (the rest of the family over-ruled me) since we discovered she was a he is the absolute opposite. He is slow, actually walks around in his ball. Will just sit on my lap and be stroked. Even in the playpen he never runs. Basil, my original hamster, who now looks like a sumo compared to the other two is somewhere between the two of them. He likes to run around in his ball but doesn't use his wheel as much as them. He comes out as soon as he hears us and begs for food, obviously is very fond of me, he follows me around in his ball and will run all over me in the playpen but if I pick him up he bites. He is the only one of the 3 who does bite.
Sorry for the long post - I am just fascinated by them all.