baltimore arena area
The Arena itself isn't really surrounded by the world's most top-notch establishments - I think there's the Godess Showbar and the Holiday Inn with the 70's revolving lounge on top.
Within reasonable walking distance is the Harbor Court Hotel, which is incredibly nice in a classic sort of way and is usually where visiting celebs stay. The restaurant there is also excelent for a hotel restaurant. Check out www.harborcourt.com
Another hotel is the Pier 5 Hotel, which aims for the Ian Schreager/Phillipe Stark genre without quite reaching it. It's right on the harbor by the Aquarium and such. Check out www.thepier5.com
If money is no object, then I'm guessing you can afford cabs (or try the Water Taxi!) - in which case, stay at the Admiral Fell Inn in Fells Point. Check out www.admiralfell.com
There are better choices for eats and drinks in this neighborhood. Very close by is Baltimore's pride and joy restaurant Charleston (www.charlestonrestaurant.com), which is a must-try. Also, a block away from the Admiral Fell is Kali's Court(www.kaliscourt.com). Not as sublime in preparation and presentation as Charleston, but the product they serve is top-notch.
Plenty of bars/clubs in the neighborhood as well, but they're hard to recommend without knowing anything about your prefrences. Feel free to e-mail me. A good one (though blessedly unglamorous) in Fells Point is John Stevens - a great place to drop in for a beer or six, some steamed shrimp, and mingle with some crusty locals.