Best, thin-material, loose-fitting lounge pants?

victoria secrets!! not the PINK stuff, like the victoria secrets body stuff. i got some on clearance in the VS store in seattle... and theyre the softest comfiest thing ever. (think sharnk in the wash though, but they were too big to begin with)
 
There's a Canadian company called Lululemon Athletica that makes a lot of lounge-type pants. They have some stores in the US but I'm not sure about the East Coast. They have lots of sizes and are super-popular here. You might be able to shop online or at least check them out. www.lululemon.com