All castles in Heroes 3.

You're right, but I think that for closing in and dealing damage, faster creatures are preferable...

It depends on who you're up against... If it's against slow units, then your slow units will also have time to reach them. But if it's against fast units, then the fast units will come to you, most likely right into the range of your dwarves (for example). And I usually use a large number of fast units to kill archers, and then I see who else is wandering around the field, and if there are few of them, I just place them near the archers without attacking.