I like Greenwich Aquaria. Very well maintained and semi-reasonable prices considering it's Greenwich. They have a decent freshwater fish/plant section, but seem to really specialize in saltwater...really nice stuff. House of Fins is a complete rip off, but nice to look around.
The only other non-big brand pet shop I go to is Fish Bowl in Stamford. Nice selection of fish (nothing too out of the ordinary), but the plants leave more to be desired.
Otherwise, I like buying plants from here or fish from the discus breeder down in NJ (1 hour from Greenwich).
It feels as though that you have the backwards. Greenwich Aquaria is nice to look around at House of fins is cheap.
GA has common stuff.
FoH has stuff that you have to buy off-line or find someone to buy it off of.
Not trying to be like super mean, I live walking distance from both of them.
I even talk to rick alot. The head honco guy at HoF. He is a boss.