Between the two new lenses announced, I am more excited about the EF-S 10-18mm rather than the EF 16-35mm f/4.
If the optics are close to being as good as other crop sensor UWA lenses, combined with the $300 price tag, I can see this lens selling well.
I probably would have gotten this over my Sigma 10-20mm.
Though since I no longer shoot crop, and I already have the 16-35mm f/2.8, Canon will not be getting any of my money on these lenses.
Though at least they are still coming out with something interesting.
Canon 5DIII, Rebel XTi/400D
Canon EF 16-35mm f/2.8L II, 24-105mm f/4L, 50mm f/1.4, 70-300mm f/4-5.6 DO, 85mm f/1.8
Sigma 150mm F2.8 EX Macro
Sigma 10-20mm f/4-5.6 EX, Canon EF-S 18-55mm f/3.5-5.6 II
Canon 430EX II
Opteka 13mm, 21mm, and 31mm extension tubes
Vivitar 50mm f/1.8 for OM System