Best breakfast in Duluth is Duluth Grill.
Duluth Grill
Ridiculous portions of fresh food including Huevos Rancheros and Biscuits and Gravy to help start the day, or put you in a food coma. Perhaps a slightly higher entry price at ~$10 an item, but if you eat it all and survive you've probably got the most out of your money.
If you're downtown also check out
Uncle Louis Cafe. A small cafe with a big college following for weekend breakfast. Pro diner service and hashbrowns that cannot be topped.
Finally, if you find your self out west check out the
A quaint little breakfast joint with a laid back atmosphere, nice people and unbelievable omlettes.
Remember, Perkins is only really good at 2am when the bars close. Because Duluth has no good late night eateries