How can I find or recall my horse?
Solution 1:
Cast the Alteration spell, Detect Life, or use the Aura Whisper dragon shout (longer range than Detect Life) to try to find your horse. The horse will usually be within the range of Detect Life or Aura whisper, after a battle.
If that fails, you can fast travel to any nearby location. You should find your horse waiting nearby the fast travel spot (or in the nearest stable, if you fast traveled to a city).
Tip mentioned by agf: "Rather than fast travel to a far location, go to whichever icon is the least greyed out on your compass -- that's the closest location. Then you can fast travel to there from there and not lose any distance."
For those playing on the PC, there are mods like Horse Whisper, which will allow you to call or summon your horse.
Solution 2:
If you get the Dawnguard DLC, there is a side-quest that will grant you a conjuration spell to summon a horse. Arvak allows you to have a horse with none of the down-sides.
- He's free. - The only cost is the mana to cast his spell.
- You can never really lose him. - If you can't find him, just summon him again.
- He never really dies. - If something does manage to take him down, or his summon timer runs out (which will not happen while you're riding him), just summon him again.
Solution 3:
Getting on and off the horse is a bit of a pain in itself. I guess it comes down to, do you want to head straight to the destination you're after, with as little distraction as possible, or battle things along the way, picking up ingredients, soul trapping etc...
One easy way of fast travel in the middle of nowhere, is to look on your compass for icons which indicate there is something nearby that you could use as a new fast travel point. It could be a mountain, or road-side ruin, etc...
Make a bee-line for those as much as possible once you're far enough away from your source point and want to be able to fast travel, but you're not ready/able to blast straight through to where you're going.
That said, a horse locator would come in handy after battle. I wouldn't object if they put one in. :-)