Let me start with mine:
1. Dona Maria mole sauce. I add a little heat (jalapenos, chili pepper, whatever), some agave, and peanut butter. Voila, a great mole sauce in 15 minutes.
2. Lunds Swedish pancake mix- I prefer making them from scratch, but if I'm too busy, this is the one mix that is good. I use a bit less milk than they recomend.
3. Pillsbuy cresent rolls - I roll them out and make cheese knishes with them. As good as homemade.
4. San J japanese steak marinade - yes, I often make my own marinade but this is suprisingly subtle.
5. Some of the William Sonoma slow cooking sauces. Expensive but good and easy.
Any other unusual shortcuts that people use? Please don't include canned cream soups because that is probably the original short cut.