What are you going to Taiwan for? Looks like you miss the silly Computex pricing (I used to go every year). My favorite hotels have always been the Les Suites chain:
Taipei Hotels New Development: Les Suites Hotels in Taipei, Taiwan
IHG have very average properties in Taipei. The HIX is good for status runs as its near the airport, however the HI downtown is too far from anywhere. SPG have five properties, the Sheraton is old but well located (It was my preferred hotel before Les Suites when it was the Lai Lai), and has some interesting barber shops in the back alley
. The Westin is very nice and not far from the famous Mongolian BBQ restaurant, if you can get a good rate grab it, the breakfast buffet is the best in the world I have experienced. The Four Points is new and I have not stayed there but location is OK. I have not experienced the Le Meridian or W hotels.
I dont have any comments on Accor, as I tend to avoid them given their so so attitude to frequent stayer programs.