If you buy one of those expensive stable horses (or guild prestige types) sure, everyone can ride one :) You won't get one for your class however, like Paladins and SKs. And I doubt your pathfinding will stack with it...but reguardless, you can ride horses if you buy one :)
EDIT - I should of said Pathfinding wont stack with it :)
Edited, Wed Dec 8 00:37:13 2004 by Stashy