If cost is an issue, shimano all the way.
If you want range and you have a compatible free hub go a sram rear cassette for range. 46t is not a solution for any problem that exists, but it easily causes problems.
If I were designing a system from the ground up, keeping in mind cost and how long things last, I'd go the sram free hub , but the $109 sram cassette that's posted elsewhere on this site (it's cheaper and more reliable than srams higher spec cassettes), XTR shifter for double double with forefinger (st shifter is double down with thumb push only), XT deraileur (stronger than XTR, and deraileurs break)