I like the Sigma 30mm f1.4. It's effectively 48mm on my Canon and I tend to use it when I want to use a prime and don't think that I'll need to go too wide and the f1.4 has come in handy for shallow DOF and for indoor use. These are both planned uses to a great extent whereas the Olympus and the 25mm combination would be more of a take it anywhere thing so I don't thing that having to struggle by with f2.8 would be that much of a problem. My 20D and any lens is quite a big thing and there are times when I don't want to take / use such a large camera so the Olympus / 25mm is just a combination that caught my eye in the mag and I may take a look at one in town.