Sam Woo (Mavis & Eglinton)
Perfect Kitchen (Dundas & Winston Churchill)
Congee Dynasty (Burnhamthorpe & Erindale Stn Rd) - the service is not so great (and sometimes outright bad) but I am addicted to the congee here.
Macey's (Burnhamthorpe & Wolfedale)
Food court in Dixie Park Mall (Dixie & Eastgate) - can't remember what they're called but the two leftmost vendors are pretty good. One's a seafood place.
As close to Mississauga as I get when it comes to Chinese food is Etobicoke. There you will find some of the best Dim Sum in the GTA - Grand Chinese Cuisine in the DoubleTree Hotel. I would not be vouching for their dinners though. Hope that is close enough to you.
Grand Chinese Cuisine: 655 Dixon Road, Etobicoke, ON
Cheers and Happy Eating!