Tainan City - An Aimless Guide has carefully researched and beautifully photographed entries on the former capital's attractions. I especially like the posts about Tiantan and the building that's now the National Museum of Taiwanese Literature.
Taiwan in Cycles features detailed descriptions of the blogger's bike rides around Taiwan
Wandering Taiwan is a bilingual (i.e. Chinese as well as English) blog with fairly short entries and nice photos. Most of the posts are about well-known attractions; one of the longest and most thorough is about Yingge near Taipei. The bloggers have also been to some places I haven't been to, such as Waziwei Ecological Reserve.
Hiking Taiwan is the work of Stuart Dawson, who I had the pleasure of hiking to the top of Mount Jade with last month. (The weather was foul, that's why neither he nor I have blogged about it). As I write in my guidebook, Snow Mountain is one of Taiwan's most beautiful hikes - and Stuart has winter photos to prove it.