1) Guaranteed wealth, with less people in the remaining world economy, each select person will be guaranteed a minimum salary of £300,000 per annum just to sit around. The amount can be guaranteed whether you choose leisure or work to build up your riches further. There will not be any need for taxation or thousands of debilitative laws ever again.
2) Less drivers on the roads and no traffic.
3) No poor people to look at or poverty. You will never see people who cannot afford to have children in society ever again.
4) The ability to live out your creative dreams, to implement large projects and expand your knowledge freely without constraint through art and technology.
5) Minimal politics and state control. Less humans means exactly that.
6) A clean environment where there is minimal pollution. Complete eco human bio technological homogeneity. Respect for all wildlife and nature. No factory farming for the masses or other elements of pollution ever again. No mass human waste dumped on the earth ever again. The earth will be allowed to recover from over-population.
7) No need for television or entertainment for the dumbed down masses ever again.
8) All encompassing universal technical education and knowledge. No more dumb people.
9) No more war or religion. With less humans, there will not be any need for war or mass control systems like religion. In the unlikely event of anything adverse rearing its head, security systems would be so advanced technologically that any threat would be neutralised immediately.
10) With no need for vast spending on military projects to defend individual nations as practised in the past, all funds can thus be directed towards extended life cycles or eradicating death completely for remaining humans. Breeding will be controlled by science. Nanotechnology and bio enhancement would enable individual humans to live for thousands of years.