I think I'm a certified Scotch addict.

Electrical Tape: Scotch 33 at a minimum. Super 88 is my preference though. Advantage is that 33 comes in different colors, 88 is black only as far as I can tell. Readily available at Home Depot.

Duct Tape: Black Gorilla, decently priced at Cheaper than Dirt, Though I have to look into the Nashua Tape as sometimes Gorilla is TOO sticky.

Packing Tape: Scotch Extreme reinforced packing tape: found this stuff at Staples. Heavy duty stuff yet cuts, sticks and lays well.

Masking Tape: When I want a light duty tape, I have a roll of 2" 3M Masking Tape. Cheap versatile, and leaves little residue (important when tacking temporary cables on a customers floor). 2" is handier IMHO than the more common 1".