The new listing for this 6-BR, 3.5-BA, 3,931-square-foot townhouse in the Hub's No. 1 neighborhood ends with a one-word sentence: "Hurry!" And why not? The frightfully elegant bow-front on West Brookline has touches going back to its 1860s origins, including the moldings and the mantels, and the formal dining room with a butler's pantry, but it's also got central air and deeded parking. It last traded way back in October 1991 for $475,000. Three recessions and at least one tech bubble later, and it's asking $3,295,000.