I don't wear "tactical" pants, but my "Riggs Workwear" by Wrangler cargo-pants are awesome. I've a couple pair and they're pretty sturdy - even though they're made from "ripstop" cloth it is very heavy duty stuff.
^^^These are VERY good. They're not your traditional 'tacticool' pants, but they are good stuff, and their ripstop seems extra heavy duty. Every year, our local general store usually does a sale on these that are slight factory 'blems' (and I can't tell how) and I get them for like $17/pair. Love 'em...tank-tough, comfortable, functional, and they don't stand out as much compared other dedicated service type pants. Decent color selection too.
I have Royal Robbins that I like and have 5.11 Cotton pants that are good for warmer weather, tho I'm not as much of a fan of the rear slash pockets as they're pretty deep, and as I have for my entire life carried my wallet in the rear pocket, it makes me change my normal routine or have to shift the wallet if I'm going to sit for awhile. I just traded into a couple pairs of the Tac Pro Lite version that I'm anxious to try out.
I keep an eye on The Clymb for a pair of the Fjallravens, they get very good reviews and outdoorsy folks seem to love them, but if you can't find a deal on them, they're crazy expensive. I was also in an Eddie Bauer shop not too long ago and they had some 'technical' pants in the four-way stretch material that were pretty nice, but not really 'tacticool' either.
The ones I'll probably get later down the line when $$ allows are the Vertx, they look like good, professional appearing pants...function without too much extra gaudiness.
Cheers,
BOSS