Toronto has a lot of theatre, including the biggie - Mirvish Productions, and small but great productions by the Soulpepper Theatre company and Canada Stage Company. If you are inclined, there is opera at the 4 Seasons Centre and the National Ballet Company.

ROM is a good idea and across the street is the Gairdner Ceramic museum. You might also want to take a walk through U of T, just south of ROM.

AGO is a very good art gallery, with a new front by Frank Gehry.

As for food, little Italy sound like where you want to go. Do try to go to the Danforth, home of Greektown. Also, some of the best dim sum can be had in Toronto, for fine dim sum, go to Lee Wah Heen or Dynasty, but other places are all over the various Chinatowns.

Other shopping suggestions would include Yorkville or Queen West.