I find it surreal that we bemoan the Euro-centricity of the list, yet only give 6 Pre-Columbian sites out of 30 (i.e. 20%) a clear Yes.
I would support many more of these sites - even if we have a selection of Maya sites, it will still be much less than e.g. French sites.

Cahokia - Y - the major pre-Columbian site in North America; iconic site of the Mississippi culture
Calakmul - Maybe - major Maya site, rivalled Tikal
Caral - Y - important site of pre-historic South America
Chaco - Y - iconic Anasazi site
Chan Chan - Y (as per summary)
Chavin - Y - important pre-historic site
Chichen-Itza - Y (as per summary)
Copan - Y - Maya site known for its steles
Samaipata - N - less impressive than other South American archaeological sites
El Tajin - Y - the Pyramid of Niches alone is worthy of inclusion
Head-Smashed-In - Y - (already in on different category (Agriculture))
Joya del Ceren - N - less impressive than other Maya sites
Machu picchu - Y (as per summary)
Mesa Verde - Y- Cliff Palace alone is worthy of inclusion; iconic Rocky Mountains site
Monte Alban - Maybe - significant Zapotec site, but less impressive than other Mexican sites
Palenque - Y - Maya site with "exquisite architecture"
Paquime - N - less impressive than the sites in the US
Poverty Point - N- less impressive than Cahokia
Quirigua - N - prefer nearby Copán
Rio Abiseo - Y - for the unique Chachapoya sites of Gran Pajatén and Los Pinchudos
San Agustin - Y - "for its beautiful giant sculptures"
SGang Gwaay - Y - for its giant totem poles
Diquis - N - obscure civilization with less relevance in American history
Taos Pueblo Y - "oldest continually inhabited village/town in the United States"
Teotihuacan - Y - (as per summary)
Tierradentro - Y - "holds the largest concentration of Pre-Columbian monumental burials"
Tikal - Y (as per sumamry)
Tiwanaco - Y - monumental architecture; major South American civilization before the Incas
Uxmal - Y - Maya site with distinctive architectural style
Xochicalco - N - less impressive than other Mexican sites

At least we should have a clear-cut yes to one of these categories.

Pre-Incan 'Mysterious' civilisations - Tiwanaco or Caral
Pueblo culture- Chaco or Mesa Verde

They are completely different from Mayan and they deserve in A-list.

Both Mesa Verde and Chaco have 5 or more votes (by my count) is that enough for inclusion?

Also 4 votes for SGang Gwaay.

Indeed.

We so far have had 9 people advocating their selections. For a Yes, we need to be in agreement (all or almost all have to be in favour, I wrote somewhere when we started). So for this category that would mean ca. 7 votes or above (it's not an exact science).

Many (Clyde, solivagant, fr4nc1sc4, myself) chose only 7 sites out of the 30, so that can never lead to a long Yes-list.

I also agree to this. However, we should have good sub-category representation like (Caral or Tiwanku) or pueblo culture can represent ( other than Inca or Mayan civilisation). They also have immense significance in Pre-Columbian history.

We have chosen only 5 out of 30 ( and covers only Mayan, Chimu and Inca civilisation). We can add at least two sites from any 2 sub-category for better representation.

I had 11 "yes" but with some alternatives to choose from later when the numbers are known and the arguments heard
We are really not all on the same wavelength on this! Some are choosing for 200 and others are apparently only choosing personal favourites. I at least am still choosing for 400 and, as far as possible trying to adopt objective " equal value" measures for this exercise
As far as I am concerned this is a process. I am interested in hearing the reasons of others and am perfectly prepared to reconsider. Many of the " maybe" have been so designated for just that purpose. I am sympathetic to the arguments of Khuft above and would expect to increase my 11 later with some of both my maybe's (and possibly) even some of my original No's!
Let us continue to evaluate the categories, let us continue to make comments where we think some site has been under or over valued - if someone wants to change immediately then OK. I would prefer to wait before making mine.
We can discuss/agree what we do when everyone has had a second say across the entire population. But also let us agree on what we are doing!

I agree with this principle.
With the maybe too strict 'Yes' selection so far we are heading for an A-list of 200, and the maybe too lenient choice of Maybe's we're heading for a combined A+B-list of around 550. But let's deal with that later, and go ahead with being critical and trying to look for different angles of reasoning. The A-list so far is very very good I believe.

This one needs a new summary.

New summary, with the threshold a bit lower:

Cahokia - the major pre-Columbian site in North America; iconic site of the Mississippi culture
Calakmul
Caral - oldest city in the Americas
Chaco - impressive remains and rock art of the Anasazi
Chan Chan - to cover the Chimu and for its size and "mystery"
Chavin - 1500 to 300BC, precedes Nazca and Tiwanaku
Chichen-Itza - Icon and representative site of of Mayan civilization
Copan - representative site of of Mayan civilization
Samaipata
El Tajin - the Pyramid of Niches alone is worthy of inclusion
Head-Smashed-In (already in on different category (Agriculture))
Joya del Ceren
Machu picchu - representing the Inca civilization; perhaps most important and iconic Pre-Columbian site
Mesa Verde - Cliff Palace, Balcony House, and unique adaptation to a harsh environment
Monte Alban - most significant Zapotec site
Palenque - Maya site with "exquisite architecture"
Paquime
Poverty Point - to represent the Mississipi culture, important representation of a hunter-gatherer society
Quirigua
Rio Abiseo - for the unique Chachapoya sites of Gran Pajatén and Los Pinchudos
San Agustin - for its beautiful giant sculptures
SGang Gwaay - for its giant totem poles
Diquis
Taos Pueblo - oldest continually inhabited village/town in the United States
Teotihuacan - for its huge pyramids
Tierradentro - holds the largest concentration of Pre-Columbian monumental burials
Tikal - no.1 Maya-site in jungle setting
Tiwanaco - covers a major culture spreading across 300BC – 300AD
Uxmal - Maya site with distinctive architectural style
Xochicalco

11 out of 30 now, I'll bring these over to the main summary page.