Living in Dubai where prices of almost anything are more expensive than elsewhere apart from buying gold, I mix my purchases between LDS and some online purchasing which is generally sent to my UK address and I collect it the next time I am there or my daughter brings it over when she visits during breaks from Uni. There are some things that are just not available here in LDSs too, so online is the only way to purchase them.
Unfortunately my favourite LDS closed down last year as the owner was ill and returned to the UK, it has been taken over however by one of the competitors and fortunately the technical team have been retained as well as one of the sales guys, so I will be supporting them in some aspects, as I know that I can walk in and have something fixed while I wait if convenient to do so.
I can't get my tanks filled or tested online
I can't and would not trust having my regulators serviced online
In 2011 I purchased from LDS
3 regulators, pony bottle, octopus necklace, long hose, semi-dry suit, mask, various clips, SMB, reels, torches.
Online I purchased
Fins, spring fin straps, 2 computers (one for my daughter, they were almost half the price of what was available here once the VAT was claimed back)