buy what you are familiar with
i would recommend you buying where you are familiar with in order to minimise surprises. District 5 is a good area to buy either for rent or stay, esp around dover close east area. the expat (japanese or otherwise) makes the rental potential at dover park view and heritage view ok and you won't be worried when you move onto another property later in your life. if i'm not wrong, you should be able to get a 3 room in either condo for your budget but i would need to double check that again. anyway i used to stay at block 12 dover close east so i have a particular fondness for that area.
choices listed not really ideal
when i was moving out of dover close last year, i also saw most of the project you listed (except those not launched yet), including projects like varsity park (whey they were launched). My personal view is most of these projects aren't near mrt + though many agents will advise you that living near NUS will have good rental potential, i personally and my clients have bad experience renting to students. They usually bargain the rent + they don't think twice about trashing the place. Unless you intend to stay for long (20 years or more), you need to consider if you need to rent or sell when you move onto a bigger unit.
Projects on the Foliage side may have japanese clients for rental as long as the japanese school nearby doesn't move away. The only issue you have to consider and calculate is what is the probability a japanese family will rent units at projects like Foliage where the size of the unit isn't what they usually look for when they have a family.
District 5's advantage is, it is near district 9 & 10. However, the parts of district 5 which are near town are the parts nearer to Buona Vista mrt. I would suggest you look around there instead if this condo you are buying isn't the last one.
Usually projects near highway like infinity are very tough to sell as buyers try to avoid the dust and noise unless they have a compelling reason to stay at these places.
Rental required in District 3
Hi everyone, My wife and I are planning to move to Singapore in a couple of months. I'm hopefully starting work at the Alexandra Hospital. Can anyone suggest a good Condo near an MRT for a budget of $S3000 per month. Also it would help if you could suggest a place to stay for a couple of weeks until we can view. Having never been in Singapore before, we are pretty much in the dark :beats-me-man: Thanks and I look forward to your valued opinions.