I have an alternate suggestion for you to consider, in addition to Brendan's suggestion of the EF 300mm f/4L IS USM. You "shoot wildlife, some nature and landscapes and would like to do some macro," and also expressed a desire for something "fast...with outstanding IQ." As Bill stated, 100mm is not long enough for wildlife, so if you're considering the 70-200mm f/2.8L you'll probably spend most of the time at 200mm. If are willing to forego IS (you probably need fast shutter speeds to freeze bird motion, which renders IS moot), you might consider the EF 200mm f/2.8L USM prime lens. In his review, Bryan closes by stating, "If you simply want thebest image quality you can get at 200mm, the Canon EF 200mm f/2.8 L II USM Lens is for you." The 200mm prime will also yield better results with the 1.4x extender than the 70-200mm f/2.8 IS


Another advantage to going with the 200mm f/2.8 prime is that it's relatively inexpensive. In fact, you could buy that lens theCanon EF 100mm f/2.8L IS USM Macro Lensfor the samecost as the EF 70-200mm f/2.8L IS USM lens (based on tonight's Amazon prices), and have a pair of lenses with absolutely top IQ and fast f/2.8 apertures, plus having a 100mm lens with true 1:1 macro capabilities and hybrid IS, which also doubles as a great portrait lens.