[easygoingman]

Hi all
I've read all of his books.
Overall I much prefer his science fiction as he's allowed to give full power to his excellent imagination, something few of his mainstream novels can do. (though 'The Wasp Factory' was a great start)
'The Business' & 'Canal Dreams' are especially weak. 'Dead Air' is far from amazing.
'The Bridge' and 'Walking on Glass' are his best so called mainstream novels but they contain fantasy and science fiction parts.

For starting with his SciFi I would recommend 'Consider Phelbas' if you prefer violence, war and explosions, or 'Player of Games' if you prefer a slower start and an eventual journey into an alien world's disgusting system.
I'm delberately underexplaining both books as I'd hate to ruin anyone's surprise!
Save 'Use of Weapons' (10/10) or 'Excession' until later though each of the Culture books can be read by itself if you decide to.

best wishes
Paul