Sugoi Zap Sub Zero tights.
In winter, I often have to run in temps as low as -12C (10F) and my regular running tights just don't cut the mustard. So I thought I'd give these Sugoi Sub Zero tights a try - something about the words "Sub Zero" suggested to me that they'd be heavier and warmer than my regular weight tights and they definitely fit the bill.
I have worn them for running and cross country (skate) skiing and so far, they've definitely kept my legs warm enough to run through the winter. They are snug fitting (not baggy) and very comfortable with a zipper at the ankle, and a flat waistband with drawstring.
A few times, when the temps hit lower than -15C, I slipped on a pair of wind pants over my tights to stave off the extra cold/wind/snow and felt snug as a bug.
Here is a description from the Sugoi website.
Highest density fleeced thermal protection with tenacious DWR water resistance and complex multi-panel contour
* Flat seams for increased comfort
* Inside key/card pocket at waist
* Lined crotch gusset for comfort
* 28 inch inseam
* Signature grip leg elastic
* Stretch drawstring with elastic waist
These tights go for $80 (Canadian) on the Sugoi website. If you have to run in the cold, you might want to consider investing in a pair.