I've been looking into this a lot lately trying to figure out the cassette range and crank I want for my new bike...here's the conclusion I've come up with:

Compact crank is better for quick shifting between cogs.
Standard crank is better for high-end speeds.

The problem with standard running with 11-27 (to allow for top-end yet still climb well) is that your cogs are effectively 10-12rpm difference once you get up near 90-100rpm (what I ride at) which means you have put out more effort to accelerate quickly. A compact allows for a quicker attack but falls behind when going downhill and sprints that reach 35mph.

An analogy...a car that goes up to 200mph over 5 (evenly spaced) gears will accelerate more slowly with the same engine as a car with a top end of 150 with 5 gears. It's exaggerated for simplicity considering the difference is 10 gears and ranging to 40mph and 37mph (11 cog at 105rpm).

I think it just depends on your style of riding mostly...I like both but would lean towards a compact for the attacking advantage....I did see a guy who rode 55/42 with 11/28...he'd fall behind on the bigger hills but then catch up again on the way down. I still think he was an idiot though XD

EDIT: Forgot to add that compacts will shave off a couple grams too.