I'm kind of split in my opinions on this. I buy my bulk items and one timers online.... base rock, uncured rock, heaters,
RO/DI unit, pumps and so on. My recuring stuff and things I MUST see before I buy I get at
LFS's... salt, my fishes, replacement filters, bulbs, cured or show piece
LR, my tanks I'd NEVER trust them to the oops truck, things of that nature.
Basically I prefer to go local but for things I can't find I snag online.