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).
65g planted tank - 200W heat - PC 192W/6700K - Eheim 2217 - Pressurized CO2 - EI Dosing