After hiring the canon 17-55mm lens I was really impressed with the focusing speed and the quietness compared with my tamron. I got some really good photos. I didn't realise quite how good it was until I put my Tamron back on so I took the plunge and I bought it along with the canon 50mm 1.4. I've not had much chance to experiment with that yet but on first impressions I think I've made the right choice.
Thanks everyone for your help and advice.
Thanks everyone for your help and advice.