We flew from LGW North earlier in the year. We got to the airport around 3.5 hours before are STD. Everyone else in our group told me that was TOO early but I like to get there early to make sure there will be no problems. One we checked in, had breakfast and a walk around the shops in was just about time to walk to the gate. So I would say get there early too, have breakfast and then you haven't got to rush to the gate at the last minute. As the previous poster said, stress at airports is only caused by unprepared travellers, who turn up at the airport too late, with too much luggage and then do not know where they are going.