A Pair of Grandstream video phones will fit the bill (although they're not Wi-Fi - so run a cable), however can you afford the bandwidth? You're talking about 250Kb/sec each way more or less 24/7
... That's close to 500MB a day, each way. OK if you have unmetered access, but I've really no idea what your internet conneactions are like... If they meter both ways, budget for one GB a day...
You'd need to do some port-forwarding in each router (UDP 5060 + the RTP ports) and 'dial' the other site by IP address - it's not hard on the GXV phones and it saves setting up proxys/sip servers/asterisk, etc. If you set each phone to auto-answer then it's not hard to re-establish the link if it fails for whatever reason.
Failing that, if you want to be PC/Laptop based - look for Ekiga...
I use a combination of GXV3000 video phones, Ekiga and my Nokia N900 to make/take video calls from my family and in-laws, although I use an Asterisk server to co-ordinate everything and we don't stream 24/7!