My very first mobile phone... got it from my parents on my second trip to the UAE in 1999, was really compact compared to the other phones back then, inspite of the C25 being a low-end phone!
The phone had very few features barring a ringtone composer, but it was really sturdy and had an amazing keypad(Haven't seen one like it since!), and fairly decent battery life(3days standby without a Li+ battery!)
Used it for three years until Summer 2002, when I picked up the S45.
My Mom used it for a while after that, and when my parents returned back to India, I got the phone back!
I got to use it again in 2003, But the battery(or something else) was in pretty bad state. and it wasn't all that usable, somehow managed with it for about a month until I got the S55.
It's still lying around in a shelf in cupboard... maybe I should buy a new battery for it and see if it makes it usable again.