For us in Perth, USS is almost like our local park.
Catch a taxi to Sentosa. The MRT(local train system) is really good and cheap, but when you do the numbers if it costs $2 for the train fare for each person and they're now charging $4 for the monorail out to Sentosa from Vivocity(it's free the other way), if there's more than one of you it's cheaper to get a taxi, which will be about $10-$15 from Orchard Road, which is where I like to stay.
Hotels I recommend:
The Quincy, a boutique hotel (all inclusive, but more expensive)
http://www.stayfareast.com/en/hotels/the-quincy-hotel.aspx
The York Hotel (which is just opposite, cheaper, and very popular with Australians)
http://www.yorkhotel.com.sg/
They're about a 5 minutes walk from Orchard Road.
Don't forget to go to the Singapore Zoo, Night Safari, River Safari and Jurong Bird Park. They do tickets which include all of the biological gardens, but at least get to the zoo if you can.
If you do the aquarium (which I find overcrowded and overrated) be sure to visit the Maritime Experiential Museum and its Typhoon Theatre (which is now a $2 add on, I think). Sentosa also has an Underwater World, which has a dolphin show, but it has seen better days.
Whilst the train and bus system (with its ez-link cards) is cheap, you'll be hard pressed to pay more than $30 for a taxi ride to anywhere on the island, and you'll save half an hour on travel time. Whatever you do, do not hire a car, that would be foolish.
USS is a great little park. Transformers is still the most popular ride there. Be sure to catch the first show of the day of Waterworld(around 12-12.45). BSG is pretty busy now that its capacity is halved. You also need to get to the Jurassic Park River Ride early, especially if it opens an hour after the park opens. The slow loaders/kids rides also get busier later on too. I would recommend getting to the Puss in Boots ride within the first hour of the park's opening.
'Madagascar', 'Shrek 4D', 'The Mummy, Lights, Camera, Action!' almost never get busy, so go as many times as you want (they're great places to cool off in the afternoon).
And not forgetting my Singaporean blogger of choice, Dejiki. Just think of him as their 'Slick'.
http://dejiki.com/