Ideal for a short stay
I stayed for 8D7N in Taipei and was running out of things to do by the 3rd day. Shopping wise you'll probably get better deals at the alleys in the Eastern Shopping District @ Zhongxiao Dunhua for young adults. The fashion offered at Wufenpu and Ximending are more catered towards teenagers. Food at the nightmarket is relatively cheap and nice too.
Insider Tip:If you intend to go clubbing, some clubs at Hsin Yi District (the hottest clubbing district in Taipei) offers a lower price or even free entry for ladies on Wednesdays. However with that said, the clubs during Wednesday nights could be relatively empty as it's still a workday. For a better clubbing experience, go during fridays or saturdays.