Electric,
This isn't about the Valsalva maneuver. Your problem is that your breathing is unregulated, like you are saying. VM or not-VM are questions of breath regulation and control.
Pause when you are getting out of breath. No need to put the weight down. Simply stop and get a breath or 2 before going on. I do this sometimes. As I always remind myself: remember to breath.
As for holding your breath during a lift, well here's my anecdotal story:
When I was 16 I suffered a contracu head injury that resulted in a brain contusion and the loss of my ability to smell. At 16 I was also really into weights. The doctors said not to lift or exercise for 9 months because the increase in blood pressure could potentially could cause more brain damage. Anyway, being 16 I of course did not listen. I thought I would lose everything I had worked hard for and would have to start all over if I followed their advice. My parents and I fought about it often. During one of my checkups with a neuorologist my mother mentioned to him that I had been lifting weights. He had a long talk with me about head injuries in football and martial arts (both of which I was in to), as well as why I really had to stop. Part of his explanation entailed the story of a patient who was a football player and honors student at a local private school. This fellah was military pressing 185 while holding his breath one day and BAM! he ruptured some blood vessels in his brain. I remember the doctor finishing with this: "The lack of blood to that region of his brain killed off the surrounding tissue. Now he's no longer an honors student."
I don't know the theoretical arguments behind holding vs. not holding or how its done, etc. But I do know that I was told not to work out for 9 months--again, because of blood pressure--and I was told about a guy who lost his gifted intelligence because he held his breath one too many times -- also because of blood pressure.
So, can it hurt you? Yes. Hell yes. Equalizing pressures? Coming from a guy at StrengthMill, T-Nation, Westside, whatever, the idea does not hold weight when compared to the collective opinion, backed by a greater intellectual prowess and medical expertise, of neurologists, who are intimately familiar with brain damage and things that cause it.
Breath...breath often.