I have bought a couple things from diversdiscount with no problem.
Many things from LeisurePro with no problem.
Simply Scuba has some decent prices but the shipping to me was expensive and took a few weeks.
DiveInn, in Spain, I have bought a few things from and the shipping is reasonable and always on my doorstep in 4 days.
I will also throw in Extreme Exposure, they are a local dive shop to High Springs Fla. but have a thriving internet business. They have BY FAR the best guarentee, use the gear for 30 days and then return it if you want for full refund. They carry Halcyon and Scubapro that I know of right off.
At first I bought stuff from a local shop when I was learning about the gear but since then I do not. Most of the stuff I get is top notch and it is known for its robustness so the year or so warrantys are not that big of a deal, and seeing that one can generally get stuff for half price on the internet, well...
My take on the issue is that if I use the LDS staff for knowledge I will buy it from them, I don't talk to them for an hour and go home and buy it on the computer.
I have not had that great of experiences with dive shop employees, they need to sell what they have. I prefer to research the living innards out of something, post many questions on this and other boards, then make my decision.
Tommy