To me, a good architectural design is a structure that has many uses at the same time appealing to the eye. It also has to be beneficial to the public.
Example. This picture of a staircase wrapped around like a Rubik's cube (don't ask me what it leads to. I don't know) is useful at the same time useful. Another example is the Integrated Resorts. It does look appealing yet at the same time it is very useful)
HDB Estates like the on the right (yes that's my house) are often dull in their design. But then again, its not suppose to. Just one giant box of bricks with lifts, houses and staircases. HDB Flats do come with amenities like a workout centre and a playground.
So HDB Estates are very useful. Then again. Since when isn't housing important? Unless people don't live in houses. But that's a different story. Anyway. They are useful, but not exactly appealing. The color scheme vary from block to block.
With that. I am done.
Rubik's Cube staircase: http://www.flickr.com/photos/daryl_mitchell/3561451558/in/photostream/
My Block: http://www.h88.com.sg/hdb/pasir_ris_street_21/images/pasir_ris_street_21_0250_00004.JPG