Rear wheels on tough use bikes are one of the few things I will spend stupid money on. Over the past 17 years I have broken one spoke yet worn out 6 rear wheels. Touring roll weight > 250lbs Commuting roll weight 220lbs.

If you live in a larger city head to one of the shops which caters to commuters. Buy either hand built wheel or prebuilt which was given pre-sale love. Ride on it for two weeks and stop by the shop for a check-up.