I have no problems, I do allow some extra time though,

My usual carry on is the following

3 (or 4) - Digital SLR Cameras
6 - Lenses
2 (or 3) - Electronic Flashes
9 - Batteries for Digital SLR cameras
24 - sets of rechargable "AA" batteries
3 - Pocket Wizard Radio recievers
1 - Pokcet Wizard Radio Transmitter
1 (or 2) - Apple PowerBooks
1 - Radio Scanner (domestic travel)
1 - Palm Treo
1 - iPod
1 - Car/Plane power inverter
6 - Chargers/Power Supplies
1 - Ethernet Hub
12 - Cables for various things

There are a few other things I know I am leaving out (like optical mouse).

I travel heavily domestically and internationally with no problems. I get stopped at SFO somewhat often, but most photographers I know get stopped at SFO often to have their gear swabbed. At Narita if you have a lot of gear they may empty your bag into trays then x-ray the bag empy.