hey TS...4-5 days, i serious suggest you to stick to 1 or at
most 2 cities. Taipei alone, you can shop and tour for 3-4 days,
and if you bring your partner along, she will shop till drop.
standard shopping places in taipei is 九fen and wu fen pu, and
not forgeting their night mkt. if clubbing, go luxy! nice
place..hehe...but luxy will be coming to sg for a tour, so probably
you can give that a miss for the moment.
have time, can go hua lian too. if on the way, go sun moon lake,
and dun forget to go for thrill rides at wen hua chun.
now im tempted to extend... :P