Budget up to £200 and happy with new or VGC second hand. It'll be used for wildlife and birds mainly (95%) and primarily in Africa and Australia. Probably not too big/heavy would be best, if possible. I am thinking maybe 300mm would do but 400mm would be great if I can find one. Needs to be very decent quality, but maybe not absolutely top notch due to budget constraints. Decent resale value is an issue as I'll probably get a bigger top notch lens in time. I am thinking of the Sigma 70-300 APO, Canon EOS EF 75-300mm f4-5.6 AF, 400mm f5.6 SIGMA HSM and Sigma 135-400mm f4.5-5.6 APO, but this list primarily based on what I have found on second hand market so far. Any user experience of these would really be helpful. I guess the Sigma 70-300 APO is a safe bet, if decent, as would be only £140 new.