Resurrecting an old thread, since a lot of people are travelling for the holidays. Here's a few that I know of. In fact, it's as long as some of lawmen's posts.
GTA:
Toronto, S/B Leslie Street at Lawrence Avenue, daytime, laser
Toronto, E/B Lawrence Avenue at Tremont Ct, daytime, laser
Toronto, Avenue Road at Roselawn Avenue, random daytime, laser, usually during school hours when speed limit is 40 km/h
Toronto, S/B Hwy 400 where it changes to Black Creek Drive and speed limit drops to 70 km/h, radar & tow truck
Toronto, Hwy 400 N/B at Rutherford Road overpass, daytime laser
Toronto, Don Valley Parking Lot S/B near York Mills, radar (TPS Hwy Patrol)
Toronto, Gardiner Expressway W/B near Parliament, day/night, radar/laser on the only part of the Gardiner with a shoulder, where three lanes squeeze down to two, officers also looking for people driving on shoulder in heavy traffic to get a few cars ahead
Toronto, Lakeshore Boulevard E/B at Logan, officer sits on Logan with laser and clocks traffic coming off the Gardiner Expressway
Toronto, Lakeshore Boulevard E/B between Park Lawn Road and the South Kingsway, laser
Mississauga, Airport Road between Northwest and Orlando Drive, radar
Mississauga, Eglinton Avenue right at the 401 interchange, laser
Mississauga, Hwy 409 entering Pearson Airport in the 60 km/h limit (ARE YOU KIDDING) area, laser, officers sitting near "cellphone waiting" cars
Brampton, Hwy 410 N/B approaching Mayfield Road, laser
EASTERN ONTARIO:
Ottawa, Hunt Club Road W/B & E/B at Paul Anka Drive, laser
Ottawa, Hunt Club Road E/B just before Merivale Road, radar
Ottawa, Merivale Road N/B just south of Viewmount, radar
Ottawa, Riverside Drive S/B at Nelligan Lane, daytime weekdays, laser and radar (Exercise extreme caution, officers using this trap will run out barely yards in front of speeding cars to flag them over)
Ottawa, Riverside Drive N/B & S/B between Leopolds and Revelstoke Drive, daytime weekdays, laser and radar
Ottawa, Heron Road E/B west of Riverside Drive after the bridge over the Rideau River, daytime mostly weekdays, radar
Ottawa, Alta Vista Drive at Cunningham, STOP sign enforcement (because everyone on Alta Vista always rolls at this stupid four-way stop)
Ottawa, Main Street S/B at Toronto Street, laser/radar
Ottawa, Walkley Road W/B at McCarthy Road, laser
Ottawa, Hwy 417 at Woodroffe Ave overpass, both directions, laser
Ottawa, Hwy 417 E/B at "the split" (Regional Road 174), laser
Ottawa, Hwy 417 W/B near 417/416/Moodie Drive interchange, radar, officers also looking for people crossing the bullnose/driving on shoulder
Ottawa, Baseline Road E/B at Zena Street, day & dusk, radar
Ottawa, Bronson Avenue N/B near Third Avenue, laser
Ottawa, Bronson Avenue S/B near Fifth Avenue, laser & red-light enforcement
Ottawa, Bronson Avenue N/B, end of the Bronson Bridge across from Carleton University, laser/radar, heavy enforcement with unmarked vehicles
Ottawa, Bronson Avenue S/B at Powell Avenue, red-light enforcement
Ottawa, Nicholas Street at Laurier Avenue, all directions, red-light enforcement
Ottawa, Maitland Avenue S/B near Agincourt Road in front of the school, mostly during school hours, radar
Ottawa, Aviation Parkway N/B near La Cite, radar, RCMP hiding behind trees & signs, 60 km/h limit with most cars going 80-100 km/h
Ottawa, Regional Road 174 at Blair Road overpass, laser/radar
Ottawa, Leitrim Road, both directions between Bank and Hawthorne, radar
Ottawa, Airport Parkway entering the airport just past the taxiway overpass, radar
HWY 416:
Hwy 416, daytime, Hwy 43 overpass, laser
Hwy 416, day & night, both directions, near Glen Smail Road overpass, officer in turnaround bay in forest, laser & radar
Hwy 416, daytime, S/B, under Fallowfield Road overpass, laser
HWY 401:
Prescott area, Hwy 401 near Merwin Line overpass, radar.
Napanee, Hwy 401 just west of the Flying J under the overpass, laser.
Napanee, Hwy 401 W/B near Palace Road, officer hides behind guardrail with gravel ramp onto 401 as you come around the curve and go down the hill, radar.
Trenton, Hwy 401 E/B approaching Glen Miller Road after the two rest stops, after going around the curve and down the hill, laser/radar.
Brighton, Hwy 401 both directions at Hwy 30 overpass, unmarked vehicles on either shoulder, laser/radar.
London area, Hwy 401 W/B, heavy enforcement, Elgin Road overpass, officer on overpass radios to up to 10 cruisers sitting at on-ramp ahead.
Already covered, but... Chatham-Kent area, Hwy 401 near Victoria Road overpass & Orford Road overpass (vicinity of Highgate & Ridgetown), laser/radar, usually one officer monitoring eastbound other monitoring westbound, officers include ontariohighwaytrafficact.com's very own hwybear. More enforcement on this part of the 401 than anywhere else, more than 50% of the time there will be officers on the road here.
WINDSOR/ESSEX COUNTY:
Windsor, EC Row Expressway at Central Avenue overpass, radar
Windsor, EC Row Expressway near Huron Church Line, laser/radar
Windsor, Riverside Drive at Devonshire Road, radar, officers also looking for people using right turning lane to pass slow traffic in through lane or driving in bike lane when traffic backs up at Walker Road
Windsor, Walker Road S/B at GM Transmission plant, radar
Windsor, Division Road both directions in front of Leon's, radar
Windsor, Dougall between Cabana and EC Row, radar
Leamington, Point Pelee Drive, officer hiding at the gates of the cemetery or behind the sign for Freddy's, radar
Kingsville, Highway 3 at Arner Town Line, marked unit with radar
And for those of you going through the United States...
MICHIGAN:
Taylor, I-94, between Southfield Freeway and Middle Belt Road, almost continuous enforcement with laser, marked/unmarked units
Romulus, Merriman Road (which runs into Metro Airport), unmarked/marked Romulus Police & Metro Airport Police, entering the airport and along the road through the airport, laser (LOOK OUT!)
Romulus, I-94 between Middle Belt Road and Wayne Road, unmarked units working in pairs or threes, laser
Romulus, I-94 at Wayne Road overpass, officer sitting on the on-ramp with laser
Farmington Hills, I-696 E/B just east of the I-275 interchange, laser
Allen Park, Southfield Freeway between Van Born and Rotunda Drive, laser/radar, officers on shoulder and the ramps
Livonia, I-275 between 6 and 8 Mile Road, unmarked units, radar/laser
Belleville, Belleville Road both directions near the bridge over Belleville Lake south of I-94, laser
Belleville, I-94 at Belleville Road overpass, Van Buren Police under the overpass with laser/radar
OHIO:
All interstates, everywhere, all the time, radar/laser/pace cars/aircraft/pressure pads/road markings with stopwatch timing, Highway Patrol stop at 2-3 mph over limit and ticket at 4-5 mph over limit, heaviest traffic enforcement of any US state
AND SOME OTHERS:
Lawtey, Florida: Over 50% of city budget comes from traffic tickets, police do traffic enforcement and nothing else, don't drive here, avoid if possible, police ticket for driving as little as 2 mph over limit, also stop for driving too slow (5-10 mph under limit), usually issue multiple tickets on same stop
Waldo, Florida: Same as above
Linden, Ohio: Same as above
Summerhill, West Virginia: Same as above
One other travel tip: If travelling by air, the earlier you show up if there's a major weather situation, the easier it will be to get re-accommodated if anything happens. (Glad I wasn't working these past few days...)