It seems Hamilton has Toronto, Edmonton has Calgary, and Winnipeg has Saskatchewan. Whenver Ottawa is in the league, there could be some kind of rivalry between Ottawa and Montreal.
What is B.C.'s biggest rival? They don't have one clearly defined rival that I can see.
BC fans know which team or teams they like the least.
The Lions have no rivals. They are head and shoulders better than any other team. It's the Lions, then all the rest. Let the games begin! 
The rest of the entertainment in and around vancouver.
Every CFL team is BC's rival. The best team this decade is probably hated by all other teams.
Wouldn't the best team this decade be the Edmonton Eskimos?
Whereas the argos biggest rivals are the Bills
The Argos should play the Bills, on a Canadian field at the Rogers Centre. We'd kill them, and leaving every Canadian Bills fan to question their allegiance to an American team.
there are no Canadian Bills fans, only wannabe americans :twisted: 
Depends on how you define a decade and what year it starts. With me it starts in 2001, since the new time era started with the year one, not the year zero.
So after defining that, yes, and it pains me to say this but the Edmonton Eskimos with 2 grey cup wins and one grey cup loss have been the best team this decade.
don't the argos need a QB first?....OH WAIT...they're playing the Bills...HAHAHAHAHA
BC is always the odd man out on the Labour Day rivalry weekend.
In the 80s the big rivalry was with Winnipeg but that has died down a lot. ( Although I think Bomber Fan has a serious hate-on for all things BC.)
Saskatchewan-BC is always a big game here but the Riders have that Chicago Cubs lovable loser thing going so its hard to really hate them or their fans.
I think right now the biggest rival is Calgary because of all the trash talking between Geroy and the Stamp receivers this past season.
It changes by the year though.
it was edmonton in '05, cuz they ended the streak.
Now why would the decade start in 2001?
Good question, I'd assume Edmonton or Calgary (more likely Calgary) would be the biggest rival, but they really don't have a geographic connection to any other team...
Now, if Halifax could just get a team, there'd at least be an east coast-west coast thing going on!
I can't understand why ANY Canadian has an allegiance to an American team!
because there was no year zero, so the first decade was from year 1 to the end of year 10
the second from year 11 then end of year 20, etc
Getting back on topic, with Vancouvers hate of anything Torontonian, and the 04 grey cup defeat, there is likley some short term hate
Last year I think BC’s biggest rival was Montreal. Simply because they were the top teams in their division and every one of their matchups was always very hyped.
A decade covers 10 years or from 2000 to 2009. Thus far, BC has been better than Edmonton this decade because of more wins, 2 grey cup victories plus 3 consecutive first place finishes overall. However Edmonton does seem to be the most hated team in CFL.
A decade doesn't cover 2000-2009, it covers 2001-2010, because the first year was year one not year zero. Therefore like Argos Fever stated the decades are 1-10, 11-20, and so on up till 2001-2010, of course this is just arguing semantics.
Anyways I wouldn't say each team has one rival. For example I would consider Winnipeg, Calgary, Edmonton, and B.C. Saskatchewan's rivals.
true but i would also say mtl..for the mere fact they alwayz have great games and they vs on labourday