Ride em.  Trim em. Try em.  Chop em.

It's a personal thing.  Some prefer slimmer for x-ups and such.  I'm leaving my new ones a bit wider for controlled flowy riding (to old and hurt for silly tricks) and street stuff.

Give em a go and see what you like.  Just remember you can make em slimmer, but not wider

Smithy

i had standard width bars for ages, then i rode my mates bars which had the brake on the bend lol and i loved them. duno how long my bars are but theres a couple of inches of i think. pretty thin. i prefer them for street too. and cant tell the difference dirting.

i have varried alot, from 580mm 620, 640 and now 680

680 is definately my favourite as it gives more control and i can still x-up and barspin no problems