- CallRecorder (free) / MiniRecorder (free) - both are great tools for recording your calls, especially if you need to capture key information during your discussions. Callrecorder lets you upload your recording to SkyDrive, while Minirecorder lets you upload it to DropBox and SkyDrive
- Connectivity Shortcuts (free) - very useful for quickly turning on/off your wifi or 3G. It's only a shame with windows you need to click twice to change the status. There are some other variations out there, though I believe there was a good one that also updated the live tile as well. I just couldn't track it down again :(
- FlashlightX - to turn your camera flash into a flashlight (torch)
- Gdocs - to access your google drive documents
- Gmaps - to view google maps. Not bad for getting some quick directions.
- Mouse remote (free)/ PC remote (free) - From my understanding, both are from the same developer and useful for using your phone as a remote to use your computer. You will need to install software on your computer to make this work but it lets you move your mouse, shutdown your computer. Free version lets you do all this via your wifi. There is a paid version out there as well for those wanting to access their computer on the go and/or from the office, etc.
- QR Code Reader (free) - I find this as the best QR code reader out there. With QR Codes, you use the camera on your phone to scan a phone and it will normally bring up a webpage of QR code.
- Toshl Finance (free) - great for expense record keeping with a tagging system available.
- TuneInRadio (free)- tunes into radio stations, including your local radio stations. I am able to tuen into Singapore radio stations. No headphones needed to act as an antenna, only internet access
- Tunetube (free) / YoutubeHD (free) - great for downloading youtube videos using your wifi for later viewing
- UCBrowser (free) - great alternative web browser to the standard factory version
- Voice Recorder (free) - use your phone as a voice recorder
Chatting/ social apps:
- Facebook (free) - Update your status, share photos, your location. It's also great for sending/ receiving messages in facebook, checking news feeds, notifications, etc. Microsoft just updated this one recently, so this is much more improved than it was in the past.
- LinkedIn (free) - add/ view connections and look up potential clients, etc. from your phone. Pretty handy.
- Twitter (free) - great for viewing Twitter updates. You can tweet (share status updates). The only downside with this app is that it only lets you only view the recent 30-60 minutes worth of feeds, but enough to read on the go. Hoping that they update this one in the future.
- GChat (free) - pretty good app for text based online chat
- Skype (free) - great for voice, video calls
- Tango (free) - great for video calls
- Viber (free) - great for online chat and voice calls
- WeChat (free) - great for online chat. You can also voice chat, clicking a record voice and after letting go, having the voice recording immediately shared with the other person on the chat. Great for sharing quick information or even recording words/ phrases for someone else to hear on the other side. I use it to share Chinese words to locals when I don't know a word
- Whatsapp (free for a year) - great for online chat and sharing photos
- XE Currency Converted (free) - great for currency conversions when you're travelling. You download the latest currency rates and when you're offline you can make your calculations
- Kayak (free), Tripit (free) and Worldmate (free) - these are pretty much the same more or less. It depends which one you use if you use any of these to receive your itineraries and to help remind you of your flights and other travel arrangements.
Other useful apps:
- AppDeals (free) - a great app for finding free or discounted apps
- Pocket One Map (free) - Great local Singapore map. Developed by Nanyang Polytechnic. This shows very accurate building numbers and key landmarks. I find it more detailed than Google Maps as it is localised. The search functionality is okay but I feel it could be improved.
- Gothere.sg (free) - this is not an app. But gothere.sg is a great way of plotting your way around town. It shows you directions and how much it'll cost to travel by bus, train, taxi, and by car.
- HungryNowFastFood (free) - A funny app that shows you where the nearest fast food (e.g., KFC, McDonalds) is from where you are.
- iChangi (free) - great app from Changi airport which allows you to check flight times for travelling or picking up your friends from the airport
- MyWaters (free) - this app gives you a view of the water levels in Singapore. It also gives you a view of some of the commonly flooded areas in Singapore. If you like exploring what else is happening around Singapore.
- BusGuide (free)/ SG Transport (free) - these apps are great for determining where the next bus at the bus stop you are waiting at and/or wanting to go to. I use SG Transport now, but used to use BusGuide as has good what's "nearby" functionality which is useful for finding the nearest bus stop and knowing what buses stop there and when. Both receive data feeds from local bus companies such as SBS Transit
- SG Movies (free) - great for quickly viewing movie trailers, movie times, etc. in cinemas around Singapore.
Also, if you're wondering, I was a previous Android user (used Android for about two years) and later switched to a Windows phone which I have been using for a year and a half now. I wanted to try the (then new) ecosystem to understand what suits my lifestyle.
Update 27/11/2013 - "SG Transport" is also another pretty good location Singaporean bus app to add. The what's "nearby" functionality is great at finding the nearest bus stop and knowing what buses stop there and when.