I don't shoot particularly long focal lengths and so although the Canon 70-200 F4 was tempting, I've kind of ruled one of those out certainly for the time being. Im just not sure it would get the use it deserves, especially on the crop sensor of the 40d of mine. Maybe when I swap over to full frame I'll think again, but at this time I don't think it's the right focal range for me.
I've plumped for a triumvirate of 28mm, 50mm and 100mm, which will form the backbone of all my future photos. Although I have the very reliable Tamron 17-50 f/2.8 I believe the option of a prime lens will provide more quality particularly in low light conditions. Each offers good quality glass at a competitive price. If the Tamron proves surplus to requirements that will help fund an improved speedlite, although it does offer an excellent wide angle option below 28mm.
I plumped for the Canon 100mm f/2 over the much vaunted 85mm f/1.8 option as it offers a little longer focal length, is as sharp as Wilkinson Swords finest across the range, it doubles the length of the 50mm and of course I picked it up for a song as well!
I'm hoping it will be the cherry on the top, offering the focal length and quality I want.
Of course with them all being EF lenses, when the time is right for full frame goodness all will fit perfectly too.