Quoted By:
Kilt.
Pants are the most disposable garment, and often the least comfortable. The most difficult part is fashion trends today dictate most pant designs wearing pants mid cheek.
I agree that the Prana Zion's are pretty good. I often just use Dickies double knee loose or 874 for the higher rise, and that they are fairly cheap, durable, and flexible. You can pair an exterior pair of durable pants with something like a polartec/fleece liner for warmth as well as I often do in winter.
Honestly thought, I like the way Kiwi's will wear shorts with their Swanndri's. Knee's are often the least cold. Just use gaiters and long socks/puttees underneath.
If you are in subtropical though, i'd use less or focus on comfort/humidity first unless you need brush protection.