The key to Sack's is the daily specials.
For a long time I came here and got the Symphony which is a decent turkey/avacado sandwich and some oriental noodles or one of their other eclectic, tasty sides. Or I would get one of the hot sandwiches on a sub roll like the Encore sans ham. The sandwiches here are ok, but kindof of soggy and sloppy with only mediocre bread like the Baggin's chain in Tucson.
One of my workmate's finally showed me the light in the form of the poorly written scribbles on the white board at the far side of the menu. Pretty much everything I've ordered from it has been fantastic. The bread still isn't much to talk about, but the unique sandwiches it sports like "The Blues", which is some delicious cajun chicken concoction, make me wish I could eat two.
Top it off with some of their great iced teas. They usually have a couple flavors, with the fruity/citrusy ones being the best. Make sure not to pour a full cup of the Market Spice tea though, you might choke to death. It's best mixed with other teas.