DC (can't forget DC, awesome pants)
I don't like insulated pants at all. They don't touch your legs unless you are Joe Sexton or LNP and wear girls pants. So IMNSHO I think they are not that effective. I prefer my pants loose and warmth to come from form fitting layers!!!
Fluid is onto something with talking about layers and pants that touch your legs automatically make you a douche... Or did I make that up? Either way...
I've got a pair of DC Banshee pants and they are the tits! They have a sick waist gaiter and a cord that can pull your pants up so they don't drag on the ground when your walking around in the slop. They also have an amazing waist tightening system so you can get pants far larger then you should and they will still fit in the waist.
I also have a pair of Capp3l pants that I like a hell of a lot.. They're far thicker then the DC pants and I will be wearing those on colder days.
I had a pair of Ripzones or something like that and the crotch blew out of those after a few days so I don't recommend that companys stuff.
Fluid is absolutely right when he mentions wearing layers... That's what it's all about imo. Buy yourself some nice underlayers and think ahead on how many layers to wear when you go out. Imo getting something fairly light and using layers for your tops and bottoms is the way to go. That way you can layer up in the colder months, and layer down on hotter days and still be comfortable. Kinda suddenly makes 1 pair of gear into 2 pairs of gear..