Rich_C, welcome to FT from another newbie!
Anyway, as most FTers here will tell you, SIN is a pretty nice place to transit in, and with 7 hours, you can also go for the free city sightseeing tour.
Check out the following threads...
http://www.flyertalk.com/forum/showthread.php?t=379285
http://www.flyertalk.com/forum/showthread.php?t=446341