I always used to shift around 2,000 and now I put my mbrp race catback on like 4 days ago and I find myself shifting around 3,500 every time. Trying to break out of that quickly and get back to around 2k
Seems to me that the engine doesn't like to drop the revs when I shift below 3k, especially when the car's cold, and that leads to jerky shifts, so unless it's really cold out and the oil pressure is up, I usually shift around 3000-3500.
Leaving my neighborhood in the morning, I shift at about 1,500 RPM so as not to piss off everyone. My exhaust is LOUD when the engine is cold.
Morning/afternoon traffic: 2,000-3,000
Highway on-ramps: 5,000-6,000
In the neighborhood, I shift at about 2000. Since I have a loud exhaust, any more pisses people off for no reason.
In regular city driving, when not hooning the car, I usually shift around 3,500. This means I usually have good power on tap in the event that I need it. Exception: I usually run first gear up to 4,500, because it's so short anyway.
On the highway, when driving normal... I'll shift it around 1,500. But I reserve the right to drop it into third or fourth and scream at 5k+ whenever I feel the need ;).