Of course, just about ANY other part of Malaysia is better, but what I like about going from SIN to JB for an afternoon/evening is to see how different it is when you cross the causeway into M'sia. Also, there is a decent shopping mall, knock-off CDs, and cheap seafood--enough for an evening, but I don't recommend staying there. Also, nothing specifically gay to see or do, from what I can tell.
Lastly, McDonald's in SIN doesn't have shakes, while those in M'sia do. This is according to my Chinese Singaporean friend who "forces" me to stop at the McDonalds at the mall for a shake before we head out shopping. It's always my only McD's visit when I go to SE Asia.