hi people, i am wondering if any of the seniors here can help me on my decision. i have a d90 with sigma 8-16mm uwa and sigma 17-70mm. I am currently looking for a long range lens and i have been asking around camera shops but all give me different advice. i am choosing between sigma AF 70-200/2.8 macro II EX HSM and APO 70-200mm F2.8 EX DG OS and sigma 150-500mm F5-6.3 APO DG OS HSM. Any advice?