My wife and I were looking at buying two full sets of everthing (middle of the line quality and above). We live in an area that has few dive shops. We are about 40 minutes from three different shops (center of a large triangle). I contacted my favorite LDS to get a price for everything. They were basically charge MSRP and giving me a 10% discount for a large purchase. Through the internet I found a dive shop about 4 hours (and two states) away. We emailed a few times and talked on the phone. They started to know me by name after a couple calls. The price they gave me was over $1500 cheaper than the LDS. HOwever due to limitations on certain equipment from certain manufactures, he could not sell the stuff over the phone. So we took a weekend, drove up to Conn. and got all our stuff. On top of the price savings, we didn't have to pay sales tax (technically they shipped the items to us, out of state). They were very nice, gave us a free ride on there tour boat. We stayed the weekend and had a great time. Yes we spent $300 for a hotel, food, gas and entertainment, but we were still very far ahead of the game.
I know the LDS has to do what they can to stay in buisness. And it's a game of supply and demand. BUt when the LDS sells at MSRP, and another shop can give me a 20%-25% savings, on huge purchase, it's a no-brainer. I got great service, however they are 4 hours away. As for future maintenance, I will pay my LDS to do the maintenance. I will go to my LDS for training, fills and the misc. stuff needed. But money is money. I have to work for a living, so every dollar is worth shopping for.
I still feel a little guilty when diving with my LDS and the talk about equipment purchases come up. But I'm sure the instructors I'm dealing with already get this type of discount from the shop. So for them it's not an issue. For me, I have to look out for myself. So do what you feel is best for you.
Good Luck