Seven years ago, Mayor Tom Murphy's vision for the rundown Fifth and Forbes corridor was abandoned -- a victory for the critics, but a missed opportunity for this grubby part of Downtown, where the squalor hung on and was slow to change.

That was then. Now, while some shabbiness endures, there's progress on almost every side. The latest sign is the news that Fairmont Hotels & Resorts will operate the hotel that will sit on top of the 23-story Three PNC Plaza project under construction on Fifth Avenue.

PNC's selection of this prestigious hotelier is exciting. The Toronto-based organization has some outstanding properties, including The Savoy in London, The Plaza in New York and the fabled Fairmont Hotel in San Francisco. As Gary Saulson, director of realty services for PNC Financial Services Group and a senior vice president, confidently observed, a Pittsburgh Fairmont will "significantly change the face of Pittsburgh's convention business" by addressing the need for more hotel rooms at the higher end of the market.

Given the recent structural problems afflicting the David L. Lawrence Convention Center, this is a business that could stand some help. Three PNC Plaza will also address another perennial concern: boosting Downtown living. As well as the 185-room luxury hotel and ballroom, 28 up-market condos -- to be known as The Residences at The Fairmont -- will be built. The rest of the space will be offices for PNC and the Reed Smith law firm.

This $178 million development is not occurring in a vacuum. About half a block away, Piatt Place, in the former Lazarus-then-Macy's department store on Wood Street that was a linchpin of the failed Murphy plan, is currently being redeveloped at a cost of $65 million as office, retail and residential space.

Earlier this week, the Pittsburgh Cultural Trust announced that the nearby Century Building along Seventh Avenue would be converted to lofts and studios. It is all of a piece with other projects in and near the Golden Triangle. According to a recent estimate by the Department of City Planning, some $3.4 billion is being invested in projects either in the works or under construction Downtown or on the North Shore.

Still, the fact that a world-famous hotelier is ready to operate a luxury hotel in an area that seven years ago was a symbol of city decay is especially remarkable. It is also proof positive that the $48 million in public support given to the Three PNC Plaza project -- $30 million in state funds and $18 million in local tax-increment financing -- was an excellent investment. You get what you pay for in this life, and what Pittsburgh is getting is contagious excitement.