On any of SQ's A380, seat 48D (economy) is a steal as there is no 47D. It's the emergency exit for crew rest area below, so the pitch is gigantic. It's called a preferred seat, meaning it costs $50 extra. For a long haul, it think it's well worth. Beware though, there's only 1 such seat on any given A380, so it's usually in high demand.