Totally depends on the car for me. My current projects:
66 Pontiac Bonneville: 10.5" FF rear, 1-ton front spindles, duramax LLY. It is designed to look like a custom touring car that would be mistaken for a stocker by many if it weren't for the 8-lug wheels.
99 Econoline Diesel: Totally stock cargo-van appearance right down to the stamped steel wheels and E-load tires, but concealing a cold air intake, catalyst delete, 5" exhaust, and (eventually) intercooler, heavy tuning, modified turbo, and 400 RWHP.
96 Impala SS: Lowering springs, 20" wheels, but nearly stock with the exception of 4.10 gears, Torsen-style posi, and some PCM tuning. Performs mostly stock, but looks great.