I imagine Seth with blond long dread locks, that he usually has tucked under his cap, radiant smile, body language that says 'unsure of myself' but makes him look kind of cute, and clothes that are skater like but still always clean (the shirts probably pleaded) not shady or anything. I imagine him like the type of guy that has a naturally muscled body with a lot of potential of being a body bulider, but when not working out is leaning towards the chubby side.
Interesting how our picture of him differs so much...