I think, once the ASIC reach the streets, would be a week or two with high profits, once that period ends, and the difficulty rises, the profit will be -normal-
Right now I'm investing all my mining profits (1200Mh/s, 0.6BTC/day) in
Once the difficulty rises to much to keep the gpu mining profitable I would shut down my gpu's miners, and I'm talking about less than 1BTC/week with current USD prices. Thats my plan to stay in.