Just thinking back to the original post... "unique sightseeing"...

I am trying to think of unique sightseeing opportunities in
Singapore... certainly if one went to Geylang, there are
sights that one cannot see in a major North American city.
But, apart from something like that, I am hard pressed to
think of unique sightseeing in Singapore - sure, the new
arts center (or whatever the "durian building" is) is nice to
see, and the tourist areas of the Quays are nice. But if the
OP is looking for something to talk about when home (and
is looking for a "first visit" to continental Asia), I gotta believe
that BKK gives more experience.

Just the Grand Palace and a short ride on the river taxi would
make me think that "unique sightseeing" opportunities in BKK
would far outweigh Singapore. (And apologies to the Singapore
Tourist Board...)