Flew from London Stansted to Salzburg and back, no problems. Full camera backpack with two bodies and four lenses, didn't need to notify them or any other extra procedures or anything.
Gear went straight through with zero issues at Stansted, and again with no problems at W.A. Mozart Airport in Salzburg, but they did spend a good few minutes looking at the X-Ray image on the monitor in apparently different modes. Camera bag and gear inside looked quite cool on the xray monitor actually ;P
Your main concern will probably be size/weight restrictions. My camera backpack weighed up as 7.91KG (I made a point to check size/weight before packing) and the limit is 10Kg carry on. I had light gear (40D, 400D, 70-200 f/4L, 17-40L, 50mm f/1.8 II, crappy kit lens just in case), but my main concern was size, it fitted within their restrictions by about 5cm in every direction. That was with a Lowepro Computrekker AW, so size accordingly 