"Standard" 80x24
Acorn A4 74x26
Apple II 40x24
Atari Portfolio 40x8
Atari ST (ZIP for partially-sighted) 32x10
Psion 3A 60x11
Tandy CoCo 32x16
I guess some of these values will vary with interpreter, font, etc.
-- Jools Arnold jools@arnod.demon.co.uk