As Calgary is a foregone conclusion, and Ottawa doesn't have a lot of seats, I've instead focused on Toronto, Montreal, and Vancouver. Each of these cities contain many seats and are battlegrounds.
EKOS uses the metropolitan regions of these cities for their polling, so that means the outskirts as well as downtown. The following charts show EKOS's polling results in these three cities so far in 2010.
As Canada's biggest city, Toronto also has the most seats. Much of the downtown core is solidly Liberal, with a few NDP enclaves won by Jack Layton and Olivia Chow. The Tories are strong on the outskirts of the city, making Toronto's electoral map very simple. But polls in Toronto can answer some questions: can the NDP maintain their bridgehead, will the Liberals re-gain some ground around the city, or will the Conservatives breakthrough downtown?
The NDP is stuck in third, and has been pretty stable in that position, with a slight uptick over the last few months.
Montreal is also easily divided. The Liberals do well on the West Island and in downtown Montreal, while the Bloc dominates in eastern Montreal and around the island. The NDP, however, finally won a seat in Outremont, making the race in Quebec's biggest city a little more interesting. The Conservatives are not a factor in Montreal.
The NDP and Conservatives, along with the Greens, have battled it out for third place in and around the city. However, as the NDP's support is more concentrated, they have the advantage.
Vancouver is an interesting city for elections, as all three parties are competitive and all three parties win seats. The Conservatives are mostly relegated to the suburbs, while downtown is the battleground for the Liberals and the NDP.
These charts show that EKOS's city results aren't as unreliable as you might think. Their sample sizes are still relatively large (often larger than those in the Prairies or Atlantic Canada) and trends are pretty clear.
The next election will be fought, primarily, in the cities. The Conservatives have a lock on the rural vote, so the final result will come down to whether the Conservatives can start winning urban votes or if the Liberals and NDP can beat their back into the suburbs.