So, since there is a similar thread for police cars, why not transit agencies? This includes buses, trains, light rail, etc.
For me:
AMT - Montreal
http://upload.wikimedia.org/wikipedi..._Vaudreuil.jpg
York Region Transit - York Region
http://www.cptdb.ca/wiki/images/b/be...nsit_504-a.jpg
Brampton Transit - Brampton
http://cptdb.ca/wiki/images/a/ae/Bra...sit_1218-a.jpg
West Coast Express - Vancouver
https://c1.staticflickr.com/9/8179/7...58f607a6_z.jpg
I used to like GO Transit's old livery but the new Metrolinx green just doesn't appeal to me...