On my last day I got blue skies in Taroko. Had a wonderful day! Walked for 7 hours from Tiansiang to the entrance! All trails except one was closed. pictures and story on my blog
http://stefanlindholm.webblogg.se for those interested. It is translable to many languages though it is written in Swedish.
Here is my 2 cents. Everybody has their opinion on the best place in Taiwan, but my opinion is that there are very few 'must see sights', but an infinite amount of great places to check out. I have lived in Taipei for a year and get out of the city a lot, and I still have a huge number of day trips from the city that I still want to do.
If you based yourself in Taipei and did only day trips, you would still have a great time, though you might get sick of taking 2-3 hour bus and train rides twice a day.
Some recommended day trips: Jiufen and Jinguahi, Keelung, particularly the temples and view from the hill at the center, and the Night Market, Mao Kong (the gondola is still closed but even better because you can take a bus up and there are way less crowds for your hiking and tea shop experience), Sanxia, Wulai, Dan Shui and Fisherman's Port particularly at sunset, Caoling Historical Trail, and my favorite hike in the north, super remote but easy to access Sandiaoling Waterfall.
The other posts are not incorrect though. You would be missing out on a piece of Taiwan if you did not venture south, and 10 days is enough. I find Tainan overrated. Taroko Gorge is pretty awesome, though coming from the rockies in Canada it is nothing terribly new, except for the picturesque temples in the gorge. Sun Moon Lake is also pretty unique and beautiful. My personal favorite place in Taiwan is Green Island, but that might be too far for your itinerary.
If you want any specific info about itinerary planning, send me an email nickkembel@gmail.com
