I grew up relatively close to Baltimore's Inner Harbor and visited it several times. At one point I worked downtown and would go to lunch almost everyday in the inner harbor. I truely believe that the harbor is the largest tourist trap ever! I've been to several cities around the US and this is truely the biggest money sucking magnet. The truth is that Baltimore is a big crime filled mess with little to draw tourist dollars, so they created something call the Inner Harbor. Although over the past 10 years they have done some good things to rehabilitate alot of the surrounding neighborhoods, there are still pockets of ghettos surrounding baltimore and typically the trash from those neighborhoods wander in on the lightrail or metro to the harbor for weekend begging. Most of them are fake bums, taking advantage of tourists to make an extra buck. When I worked down there I noticed one woman frequently begging for money claiming to be homeless. Then one day I saw her climbing into her fairly nice buick which she had parked in the parking garage a few blocks up.
Around the inner harbor there is a wide selection of eateries and shops. Most all the restaurants are good to excellent but its your typical Cheesecake factories, Hard Rock Cafes, ESPN Zones and California Pizza Kitchens that can be found just about anywhere in the country. Most of the shops are just what you would find in any other mall as well. Bath and Body Works, Lindt Chocolatieres, Godiva, Foot Locker, etc...Again, nothing special. For a more Maryland experience, try Phillips Seafood. For a little more unique experience you could walk a few blocks past the harbor to Little Italy but choose your restaurant wisely. Most of the restaurants in Little Italy have moved away from fresh and homemade to prepackaged dishes. On one Occasion I ate at Chiapperelli's and paid $18 for a side salad, bread and one Tyson's Frozen Chicken breast with sauce and cheese on it (pasta not included) otherwise known as chicken parmesagne. Aldo's or Delle Noche are much better choices but of course you will pay for it.
There is a full spectrum of attractions. The Baltimore Aquarium while its not the worst I've ever been to its definately not the best. Most of the building is old and displays are small. They did however add an interesting Australia exhibit which was small but interesting because of the unique animals they had on display. The Baltimore science center is good if you have kids. Displays are often elementary school level. The IMAX theatre there is worth seeing but you have to pay for admission to the science center as well as admission to the IMAX to see the show. If your into baseball then you have to see the greatest baseball stadium ever built! Camden Yards! The adjacent warehouse is filled with restaurants, bars and shops that you can enjoy before, during or after a game. Boogs Pit Beef is a cant miss and tickets to the games are very affordable. Raven Stadium is also right next door but not quite the architectural feet.
Another attraction that may be worth the money is one of the harbor cruises, they can range anywhere from short rides out to fort McHenry to a dinner cruise to Annapolis. I believe one of the cruise lines provide themed cruises such as a pirate ship cruise and a duck boat tour. There are also ferry boats that shuttle between the inner harbor, fells point and Ft. McHenry all day and night so dont drive around and waste money on parking garages like some people.
At night, be sure to check out Power Plant Live or Fells point. There is sure to be a bar, club or restaurant that suites your style, although most places attract a younger crowd.
In summary, Baltimore's inner harbor has plenty to entertain and waste time and money on but lacks any real tourist attraction besides ft mchenry. Beware of the homeless, avoid dark alleys and travel in groups. Who ever dubbed the named charm city was probably just looking for tax dollars. Harm City is more fitting.