Depends on the conditions, traffic, etc.
If I'm accelerating to get on a service road, highway, on a large boulevard with no lights coming up soon, I usually go WOT and shift at 4000-4500rpm. I actually get better fuel economy this way, compared to keeping the revs low and taking time to get up to speed, and I feel safer breaking away from the traffic and not being surrounded by cars.
If there's more traffic, lots of lights, I rarely go over 1.5K-2K rpms... I love the 6 speed tranny in my Jetta, cruising at 50-70kmh it's at 1000-1200rpms.