Anyone know which polling firms are considered most accurate?

Polling is heavily contingent upon the exact wording and ordering of the questions. Thus, comparing across polling entities can be tricky since they don't use the same words in their questions even though on the surface it may SOUND like they are trying to get at the same attitude. Therefore, unless the exact same poll is repeated across time I would be hesitant to attempt to compare them, regardless of the reputation of the polling entity.