As always, it depends on what you define as decent.
Your offer is similar to the average income of a two-person household in Singapore, but you'll not be able to afford a car, maid and/or luxury apartment.
Guys, I have a similar 'problem'... if I am earning around 80k SGD, how much do I expect to pay in tax? Also, when I was in Singapore 3 years ago on holiday I noticed food in groceries store is quite expensive - especially cheese, eggs and milk? Would you say it is cheap to buy food from shops and cook at home, or it makes sense to eat at hawker centres all the time?
IRAS publishes a simple tax calculator here. It's the very first link.
As with any place you live if you try to import an "alien" diet you will pay more. There aren't many dairy cows and chickens in Singapore, though I don't find dairy products and eggs (especially) to be particularly expensive. For example, boxed UHT milk is routinely S$2.95 per pair -- about S$1.50 per liter -- at FairPrice these days, and I'd say that's not bad. Eggs are about S$0.20 each. Cheese starts about S$18 per kilo and goes up from there. Hawker markets aren't serving milk and cheese very often (eggs yes), so there is no real comparison.