Painting
Both ICI and Nippon Paint advertise fairly reasonable-sounding prices on their websites ($1100 and up for a 2BR), but once we had a sales rep from Nippon Paint actually come over, that estimate ballooned to over $2000 -- inclusive of applying sealant, which the apartment would really need, but the landlord wasn't going to pay for. The old neighborhood paint shop (Mr Lim of Lim Song & Teck Interior, tel. 81082399), on the other hand, had a much better price: $900 for the whole shebang (c. 1400 sq.ft., with high ceilings and weird structures to boot), plus $150 for patching up and leveling off the worst bits of the ceiling and walls, all using quality Jotun paint. They got the job done in two days, didn't cause too much damage, did a basic clean-up and offered to come patch up any remaining bits if there are any problems; which there haven't been, yet.
A year later, the mold damage caused by water leaking in from the apartment above started to reach such epic proportions that we arm-twisted the landlord into repainting the affected bedroom and bathroom, this time with oil-based rubber sealant paint. Mr. Lim came over to give a quote ($280) the same day when called, showed up on the dot at the arranged time with his helpers, and completed the job in under a day.
Air-con servicing
I first tried a bunch of incompetents called A-Cube under the mistaken impression that I'd used them before. (I hadn't; I had used E-Cube, which did a good job, but are apparently now out of business.) After 2 calls and a few reminder SMSes, I'd gotten a lot of hard sell for hourly maid services (which I never even asked for!) and not even a call back, so I tried my luck with A-Class instead. Showed up the next day, $25 per unit, job well done and no hassles. Recommended.
Electrical
I had two ceiling fans at my old apt that I wanted to take along to the new one, but while my diploma actually says "electrical engineering" on it, I prefer to leave anything involving 220V to the real experts. (This determination got an extra boost when, while attempting to install an ordinary ceiling light, I got zapped despite it being switched off; turns out some previous genius had wired the lamps in series across four rooms, and pulling apart the two neutral wires caused a floating ground. Grr.)
I first got in touch with a guy called "Handyman Vincent", who advertises all over the net with seemingly very reasonable prices, eg. $35 to install a ceiling fan. He first quoted $70 for installing two fans... and an extra $30 to take them down first, plus $50 for transport, and oh, one's got a wall controller, so that'll be $25 extra, and the other's got a light you say, well that's $25 more, and you say you want to replace the old lights, which will be extra, and...
By this point, I knew I was being taken for a ride, but I'd noticed that the air-con servicing guys also do electrical work and so I asked them for a quote: $120, full stop. And that's how I was introduced to the remarkable Mr. Chew (tel. 98533288), a gruff Chinese uncle who speaks powderful Singlish at the volume of a drill sergeant and whips any electrical device into submission. In addition to moving the fans, he restored the original lights in the old apt, debugged broken lights in both the old and new apts, installed casing for the new wiring for the fans and installed a couple of tricky ceiling lights. The total bill for >5 hours of work at two different apartments plus all parts came to $205, rounded down to $200 and tip refused.

Moving
This was an easy one, as I'd used these guys before and they did a good job both then and now. Jenny Movers, tel. 97557813, $280 for moving 2BR full of furniture, plants etc down three flights of stairs and into the new apt. These guys are fast: whether the job is small or big, their modus operandi is to send down a big truck with around 10 Bangladeshi guys, who wrap up everything in plastic and can finish a move within an hour.
Hardware
These guys have been mentioned before, but I'll plug 'em again: Handy-Man, tucked away on the 4th floor of Shaw Centre (at Orchard/Scotts crossing), is probably Singapore's best hardware store. The hardcore DIYer can probably get better deals for bulk sales elsewhere, but if you're just looking for bits and pieces like a small can of wall paint or a couple of ceiling hooks, they've got everything you need plus competent advice for free.