If Jesus was abnormally ugly among his peers Judas would not have had to point him out with a kiss. I say the same thing about Jesus hair length, but that's a separate issue. I don't believe Jesus was abnormally ugly. The part of the Isaiah 53 verse says that people would hide their face from him (as I take it, turn their face away because he's so ghastly ugly they can't handle looking at him) refers to his total disfigurement and dehumanization in crucifixion. It remains that he may have been of a normal appearance.
Like the above reasoning if Jesus was overly beautiful all Judas would have to do is say, "They're in the garden at Gethsemane. Grab the gorgeous one and you'll have the right man. By the way, thanks for the coin." Also, an overly beautiful Jesus would violate the part of this passage plainly stating that he had no overt beauty.
Those are my two cents. As a bonus, I'll quickly mention about a long haired Jesus, and while I'm at it a black Jesus. >.< All due respect. As my points above indicate Jesus would have been more or less an indistinguishable member of the majority population of the Israel of his day. In Jesus culture as he lived it was a shame to have long hair, as it would point out that you have not completed your vow to God (referring to Num. 6:1-21). So unless more than a few of his disciples grew long hair and were black it's improbable that Jesus would have had long hair and have been black, either or both.
My main point in all of this is simply that Jesus looked like a rather normal average citizen in his culture. He was Israelite by birth and would have looked Hebrew, spoken the language of the day, and lived and breathed as a descendent of David (biologically through Mary). If he did not look like an average citizen (granted, possibly of some lesser beauty, or simply not good enough looking to be popular because of beauty) there would have been much more mention of his appearance, and I believe there would not have been the difficulty in identifying him in the garden.