I bought a pair of what I think are "standard issue" boots on amazon because they were really cheap.
They are easily my most comfortable pair of shoes, and I wear them almost every day.
(I'm not in the military, I just needed some work boots)
http://www.amazon.com/gp/product/B003AT0CD8/ref=wms_ohs_product
Seriously, get some military surplus boots:
http://www.amazon.com/gp/product/B003AT0CD8/ref=oh_details_o00_s00_i00
These are the most comfortable shoes I own, they're rugged as hell, and have been to hell and back with me. I still wear them almost every day.