I'll say Icelandic's, they are fearless, brave, loyal, smart, smooth, fast, friendly, gentle, easy keepers, hardy, can do anything other horses can do, don't need a mounting block to get on, can go all day, and they have personality plus.
Colour wise - Paint/appy (Their x is lovely too)
But really, it all depends on the horse. I mean, I've ridden some horses of the same breed & I hated one, and loved to other.
I must say though, arabs are wonderful (although I am biased as my baby is one).