Don’t get a taxi, get the MRT unless you have loads of luggage, they even have lovely old ladies to give you change. Just don’t eat or drink on them, it’s an expensive fine. As CFH said Din Tai Fung, there’s also a good vietnamese place down there and a kaya toast place (it’s an acquired taste you may not want to acquire). There’s a place which also does the best salted caramel brownies. They’re expensive but worth it.
There’s also some super random stuff as well. Squid balls. A place that does pastries but it’s like greggs in an alternative universe (salt and pepper crab etc). Cream puffs. Just wander around and buy stuff that looks interesting. The times I’ve been to Singapore for a conference its always been in Raffles City so I’ve eaten mostly down there.
If you can be arsed with a short MRT ride, JiBiru on Orchard Road (Somerset MRT) is my favourite bar and there’s a really good restaurant in there called Kilo but I have a feeling it’s closed now.