If you're looking for a good horse early on in the game, then look no further than the horse you get as Bonnies gift. It's a golden/whitish stallion that you have to chase in a mission for Bonnie. If you lose your horse (its killed) then don't worry too much. Because you can either buy the deed to the Kentucky Saddler from any general store for $1500. Or, if your honor/fame is high enough, $750 due to discount.
Alternately if you come across a whitish golden horse in the wilder, it is the same breed as the Kentucky Saddler and so if you can break one in, which is slightly longer than most horse breaking you have yourself a pretty quick horse.
Also, the American Standardbred ($1500/$750 deed) black horse can also be found in the wild and it is of similar pace to the Kentucky, so look out for them.
Horses bought by deeds can be respawned via selecting the deed from your satchel if you should lose one via death. So don't worry if you spent big money on a deed & it gets killed.
Added by: sphynxx May 22nd 2010, ID#2740