Also, what kind of trailer do you have; slant load, straight load, stock, etc? I can understand not hauling tacked horses in slant or straight loads just because there isn't room, but how about those folks who pull stock or stock combo trailers?
I'll start us out, I pull a stock trailer and I normally haul my horses fully tacked; saddle, bridle, the whole nine yards. Mostly, that's because I don't have a tack room in my trailer, but it's also because I like to be prepared when I get to my destination and not have to spend another 5-15 minutes getting tacked up and ready.
And just for grins and giggles, here is how Dobe hauls. I snapped these pix with my phone a few days back while we were checking cattle.