I'd say it depends on the level you're talking about.
At the junior level there's a clear top 5 (CAN, SWE, RUS, USA, FIN), the order changing year to year, followed by an equally clear 3 dark horses (CZE, SUI, SVK), with the Czechs ahead of Slovakia and Switzerland, each of whom can medal in a good year but probably not win gold.
At the olympic (best on best) level there's the overwhelming favourite (CAN), followed by three primary contenders (SWE, USA, RUS), followed by the perennial dark horse (FIN) who will fight for a medal every time, but probably not gold. Then comes the occasional dark horse (CZE) who will fight for a medal every now and again. Finally there's the long shots (SUI, SVK), with Switzerland in my opinion having passed Slovakia, who are unlikely to fight for a medal but can occasionally challenge the top teams. Then there's the rest who can occasionally make the QFs over one of the other teams but pretty much never make it further (the exception being BLR in 2002).
At the WHC level the dynamics change a bit. The north american teams (especially USA) fall here due to the NHL playoffs still going on. If they happen to have good players missing the playoffs they are up there at the top, if not they are more like 4th or 5ft. Overall I'd say the rankings for the WHC are something like this (depending on who's available from the NHL:
RUS 1-3
CAN 1-4
SWE 1-5
FIN 2-5
USA 2-6
CZE 3-6
SUI 7-8
SVK 7-8