I had heard that the detail becomes crucial in Singapore. What London will let you get away with, because you have a UK passport, Singapore won't. And of course then you get hit with charges you weren't expecting etc.
I had also heard that Singapore Airlines have changed their requirements and unless it says on the visa stamp in your passport indef leave granted etc then you won't get the extra. Maybe they have been stung a few times eh?
We took a plastic folder with all our documents in. I didn't want to take the chance it got lost.
In hand luggage, we had 2 changes of underwear, 2 pairs of socks and 2 tshirts each plus toiletries. Once rolled up, it took up hardly any space in the bags. We booked 2 rooms at the Changi Hotel at Sinagpore Airport which costs about £20-ish and which had a big double bed, ensuite, TV, phone, tea/ coffee making facilities and was a great place to stretch out properly and have a bit of privacy. If you aren't doing a stopover I would recommend that. Or the new Crown Plaza hotel which opens this summer. Both are inside the airport.
For suitcases, I would pack an umbrella, and lots of layers. I would also wear anything a bit bulky which although awkward to carry is much easier than having to heave it around in a suitcase taking up valuable space.
We did bring bedding with us-what a waste of time that was! We had to go to buy duvets and pillows anyway on our first day here and could quite easily have bought something there. We did the cheap OAA route and that I would change if I had to go back and do it again.
And although Guzzler is quite right in his list :p, he did miss Tuna Pasta Bake Sauce mix, which is quite frankly essential!