I was going to Markhart for different quests but I couldn't fast travel, so I decided to steal a horse in Whiterun to get there quickly. On my way to my destination a dragon started attacking me and I was like: "Damn, I'm an assassin with just a bow and a couple daggers. How am I gonna kill this monster?" But then I started shooting arrows from my horse and I noticed it was pretty easy, especially when I was slowing time with the archery perk. I could run away from him and then destroy him with my (not really) superior fire-power.
So, what do you think about fighting from your trusty, or stolen, horse? Do you like it? Or you think it's just useless?

It's useful, better than riding around on your horse, get off to fight something, it runs away or dies and you just no longer have it o.o

Although fighting on it isn't all too epic when there's only two ways to hit.

I never got into the horse combat. Trying to hit things with stubby daggers on a horse as an assassin just doesn't feel right. As for dragons, I use my second set of skills and conjure up a dremora lord as my dragon chew toy. Then I proceed to carve a piece out of their hide.