Anything from Panasonic or Polycom would be fine.
Analog multi-line desk phones are gradually going away, being replaced by IP phones. If you want to buy something with more future potential, get one or more OBi 1022 or 1032 phones. These phones have the ATA function of the OBi 20x series built in and don't use an external ATA. Yes, they will work with any SIP VoIP service provider or PBX, as well as with cloud-based providers, including Google Voice.