I brought my bike into my LBS today and talked with the mechanic about swapping components to get some lower gearing. I currently have a 34-50 compact crank and 12-26 nine-speed cassette. He said replacing the crank with a triple would be cheaper and easier to do than changing the cassette and rear derailleur. In looking at Sheldon Brown's gear calculator, the setup with the triple would lower my lowest gear from 31.8 inches to 28.1 inches. Is that really a significant enough difference to justify the cost of changing components?