Ok so I'm happy with my Canon 50mm f/1.8. My Sigma 10-20mm + flash does an ok job sometimes and my Canon 28-105mm with the flash also does a good job. While I've found ways to use my flash to aid in low light areas I still feel like using the natural lighting is the better way to go. The issue I have is with my potential next choice. I'm thinking of the Tamron 28-75 f/2.8. I hear, and have seen, that its a great lens. Its only really one stop off my current Canon 28-105mm, and isn't as zoomy as that. Is it worth paying the £270 for the extra stop and a sharper lens? I could get the Sigma 24-70 which is obviously wider but not as sharp, so I hear. Decisions decisions...