Icarusflies, this is one of those topics that's been batted around a bunch.
If you search on the issue, I think you'll find that, where there is consensus, it is that people diving dry are OK putting the weight belt under the harness, but people diving wet (in other words, without redundant buoyancy) are better off being able to drop weights. That means having the weight belt outside the crotch strap in back.
Tobin has a nice technique for accomplishing that -- you put the weight belt on first, but then you bring the crotch strap around to the side, tuck it under the weight belt where you can see and manage it, and then pull it down in back. I haven't tried this technique, because when I dive wet, I only use two pounds, and I put them on the camband straps.
Of course, underlying this whole argument is the concept of a balanced rig. If, with your wing deflated and at sufficient depth to compress your wetsuit, you can swim your rig AND weight belt to the surface, there is little need to have your weight belt easily removable. On the other hand, if you can't, you need to be able to get your weights off at depth, or have redundant buoyancy.