Recently I've found myself drawn to steel framed windows. Sort of old world European, or modern industrial look. I'd like the entire sunroom to be constructed of this style windows. Also the front entrance and certain interior walls and doors.
This HDB apartment is an excellent example of how subtle mix and match can be. What is interesting about the interior is that the designer opts for more modern flooring materials in the dining room, such as tiles, but still sticks to parquet in.