Home phone...only one option: SingTel. Though you can get IDD from a number of people: Singtel (001, 013 and 019), M1 (oo2, o21) and Starhub (008 and 018) are the mainstream ones, then there loads of internet ones (1151, 1551, 1553...er, can't remember them all)
Hand phone: Three main operators: Singtel, M1 and Starhub. Singtel and M1 use the same network (I think), whereas Starhub is the "new" boy, and not quite as extensive yet. Pick your plan. Pod and virginmobile also are tied in with Singtel. Prices are pretty similar, you get more off your phone if you sign up for longer. It's not ultra competitive, but there again, it's a captive market.
Cable TV: SCV. No choice in companies, if it's not wired to your house, hard luck! (Though you might want to give SCV a ring if you want to make sure)
Internet: Singtel, Starhub and pacific do modem access (56kbs), whilst Singtel and Pacific do high-speed modem (up to 512kbs). SCV do broadband cable access (1mbs) but you need to be wired up. Personally, I went on SCV, thought it was the cheapest and easiest, though others may have differing opinions. SCV does have minor slow times when everyone else in on, though I'm unsure how slow the high-speed modems are.
I think that about covers it all. What have I got?
Singtel home phone, no other IDD facitilites
M1 handphone
SCV TV
SCV cable
Would I go for it all again? Probably, I've used Singtel mobile before, no real difference. There aren't many other options for the others!!