It really depends on your budget, but you should check this out (or anything similar), from Gore bike wear : 179.99 USD MSRP http://www.gorebikewear.com/remote/Satellite/PROD_TULTRO?landingid=1208436873480O
They aren't the tightest pants out there, but "real" tight pants are very rarely (trying not to say never) waterproof because of the type of fabric used to make them.
An alternative idea would be a nylon pant (waterproof, windproof, but absulutely not warm)
that's relatively tight with a warm baselayer.
bicycles.stackexchange.com/users/417/dee-see
I have a pair of Sugoi long tights for commuting in the winter.
I add or subtract a base layer depending on conditions.
I don't really care if it's Sugoi or not; other companies make bike-tights compatible with base layers.
Maybe I choose a different brand next year?
Depends on what's on sale...
bicycles.stackexchange.com/users/None/
Foxwear makes great rain pants and jackets.
They're a little baggy, but they close at the ankle --
no ankle clip required.
They're also good layered over tights for winter riding.
I have two pair, and will use them until they fall apart (which may take some time).
bicycles.stackexchange.com/users/8/Goodbye Stack Exchange
The trick to staying warm for your winter rides is layers.
Keep in mind your overpants aren't there to keep you warn, per se, just to keep you dry.
You can wear under them pants, long johns, long warm spandex, whatever floats your boat.
That's part of why they would be baggy too.
When I used to commute in Boston through the winter, I wore thick long spandex pants under my snow pants, and that, combined with the heat generated by riding, was enough to keep me warm through -5F blizzards :)
bicycles.stackexchange.com/users/563/zigdon
REI has a Novara brand rain pant that isn't too expensive.
I use mine all year round, rain or snow.
I don't wear them when it is warm, as they tend to keep moisture in as well as out, which leads to soaked clothing.
However, I believe that is a problem with most rain gear.
I got my pants on sale for around $30 a few years ago.
When I go to the website now, I see that the men's version is around $100 in the catalog.
I'm not sure why the price difference. www.rei.com
bicycles.stackexchange.com/users/2585/ananka
I have a pair of Polartec tights from Col d'Lizard that are the cat's pajamas (or some such metaphor).
Definitely not baggy (when you see them you'll understand -- "I'm going to fit into THOSE???"), and plenty warm down to maybe 5-10F, but they breathe well -- never get clammy.
I no longer do winter cycling, but I often use the tights when I run the snow blower.
The snow doesn't stick to them and they keep me warm in the wind without overheating.
bicycles.stackexchange.com/users/1584/Daniel R Hicks
I wear my Craft Storm Tights for my winter commuting and even some recreational longer rides (I get too hot when I wear them for an interval type of workout). http://shop.craftsports.us/sports/bike/mens-pxc-storm-tights.html
They have a thermal liner and keep me nice and warm.
I also like them for the ease of use, I just slip them over my underwear and off
I go.
Not skin tight but not loose around the lower legs.
bicycles.stackexchange.com/users/2953/Glenn Gervais
I got the MEC Roubaix Tights this year
and I have found them surprisingly warm, despite that they are quite thin.
I wore them down to -15 Celsius and had no problems with my legs getting cold.
Depending on where you live, and what you consider "winter" something like this might be just fine.
bicycles.stackexchange.com/users/163/Kibbee
Winter is soon upon us here, and I'm gearing up for the season.  I currently have a pair of rain over-pants which I use during the other 3 seasons, but honestly I really dislike them.  They're baggy, requiring the use of an ankle band, and not entirely warm.  They do a decent job of keeping out water, but I don't know how they will perform with snow.  Can someone recommend a type of pants which are more form-fitting and will do well in both rain and snow?
Finding good pants for winter biking
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<winter><clothes>
bicycles.stackexchange.com/questions/1623
bicycles.stackexchange.com/users/25/Nik Reiman
The trick to staying warm for winter rides is layers. You should keep in mind your overpants aren't there to keep you warn, per se, just to keep you dry, so nylon is good - light and waterproof but not warm. Under the rainpants, tights are good and there are many brands available on the market. Obviously what you buy depends on your budget. There is a number of specialized products for winter biking, varying from pants to tights. The recommended brands include Gore bike wear, Sugoi, Foxwear, REI, Col d'Lizard, Craft Storm and MEC Roubaix. A good idea would be to use water- and windproof nylon pants, which however should be paired with additional clothes, as they are not warm. More to the point, You might want to consider waring layers, instead of specialized bike wear, given that overpants are only intended to keep you dry.
There is a number of specialized products for winter biking, varying from pants to tights. The recommended brands include Gore bike wear, Sugoi, Foxwear, REI, Col d'Lizard, Craft Storm and MEC Roubaix. A good idea would be to use water- and windproof nylon pants, which however should be paired with additional clothes, as they are not warm. You might want to consider waring layers, instead of specialized bike wear, given that overpants are only intended to keep you dry.