Golden-age Spanish national team had:
Ricky Rubio / Pau Gasol / Marc Gasol / Rudy Fernandez / Jose Calderon / Juan Carlos Navarro
Consists of really well-balanced NBA-tier players at all positions.
Meanwhile, this year’s French national team, although having Wemby & Gobert, is really lacking in the backcourt, very weak guards.
The Canadian national team has a strong backcourt (Murray&Shai), but weak at the 4&5 position.
Argentina 2004 was better than both the teams you chose for the comparison (France/Canada):
Sanchez - Ginobili - Nocioni - Scola - Oberto
(Also having a lot of talent on the bench, and most importantly a cohesive team performance and the most obvious fact of being the only team ever to get that gold medal other than the US since NBA players go to the Olympics)
Choosing between 2004 Argentina and 2008 Spain can be harder but in any order they are 1 and 2 in your FIBA teams list that have played against the US.
2004 Argentina vs 2008 Spain would be interesting but id still back in 2004 Argentina
Both teams played beautiful basketball but Argentina seemed to gel so so well. They looked like they knew each other’s games inside out and were at the end of an 80 game season