Some nice research turned up by Tom Asacker, showing that people primed with a momentary glimpse of the Apple logo are more creative than those exposed to the IBM logo...who are also less creative than a control sample.
All of which may be a little harsh on IBM who, objectively, are much less the dull and grey monolith they once were. But, as in all thing, it's the emotional response that matters.
So brands matter (surprise!)...at least when it comes to tricks with bricks.
And if your brand has real and potent meaning, which is about more than a set of adjectives in a marketing document, it can have a significant (if subconscious) impact.