Nokia 3210e

I got this phone free. But the covers cost 25UKP (officially - I've seen them for much less now). It's a pretty good mobile phone.
Ups:

Light weight
Integral Aerial
Snake Game

Downs:

Picture Messaging
Poor keypad
Calculator
Stupid ringtones with hard-to-use composer.

You can connect a data cable to this phone to transfer ringtones, text messages, graphics and phone book data.

The best thing about my Nokia 3210 is the predictive text input for English SMS message writing. It's so cool!

All you have to do is to press the key with the corresponding letter once and the built-in dictionary will show the most likely word. You can also add new works to the dictionary.

E.g. the word HELLO. Type 4-3-5-5-6 into the key pad and you'll get:
I
He
Gel
Hell
Hello, as it predicts what the mostly likely work will be with the sequence of keys.

Takes away the fustration of pressing the same key many times, and ooppps, too many times that you have to go through all the options again.