Obviously the US 1) US GDP is higher than the next four countries combined 2) US is largest producer of energy in the world 3) US exports more agricultural products than any country in the world 4) US has more manufacturing output than the next two countries combined 5) US provides more services than next seven countries combined 6) US is still considered underpopulated 7) US has 4% of world's population but is responsible for 26% of its economic output 8) US debt-to-GDP ratio was 20% higher right after WWII China has huge problems with corruption, pollution, and a financial meltdown in the works. China is dependent on US consumers; we are not dependent on their exports - can easily find a replacement. China needs US to feed its people. And whoever made the comment about China military power doesn't know what they're talking about - just look at defense budgets and if we ever got into it I doubt we would be attempting an "occupation" like Vietnam or Afghanistan. And US is only country in the world that can control all the oceans. The list can go on and on....
lol quality > quantity and further lol for comparing Vietcong to Chinese forces. China is something the US would actually be prepared for. God help whoever hits the US military with something they've been itching, preparing, training, and planning for since the Cold War.
Canada has my vote for HEALTHIEST (not largest, read thread title for appropriate question): 1. Resource based economy with gigantic oil reserves, not to mention second largest uranium producer in the world. 2. Lowest debt in G8. 3. Healthiest financial and banking system in the world. 4. Immense potential in the Arctic where Canada, arguably, stakes one of if not the largest claim. The biggest threat to Canada's economy is the ageing population. We need immigrants or Canadians need to start having a lot more babies in order to keep economic growth sustainable in the long-term. Production gains aren't keeping up. The disclaimer is my bias because I am Canadian.
correction, you need educated and skilled kids/immigrants with high earning potential (high productivity). 4 million lettuce pickers, video game players, and drywallers ain't gonna be able to support the standard of living you are accustomed to.
If this global warming thing ends up actually being real, you guys are set! I'm probably giving to much value to sharing a common language with you guys, but I think my vote goes to Canada also. Sadly, due to some youthful indiscretions, Canada no longer welcomes me through her borders. You forgot the reason part.