[IYAS9YAS]

IIRC, you could move the world's population to Texas, give each person 100 sq. ft. of space, and you would still have more than 50% of the state available.

This is what I came up with:
Texas is roughly 268,820 square miles. There are 640 acres in a square mile.
268,820 x 640 = 172,044,800 acres in Texas.

World population is approximately 6,872,200,000
That would be approximately 40 people per acre (6,872,200,000/172,044,800).
There are 43,560 square feet per acre. That gives each person roughly 1,089 square feet of space (to cover all of Texas). So to cover half, each person would need 544.5 square feet of personal space.

Granted that isn't much. Think about this, most new developments have 8 houses per acre, and average family size is 3.14 persons. So, in a new subdivision in the United States you have roughly 25 folks per acre.

[Grunthor]

Gosh I almost feel guilty sitting on my 2.35 acres. Almost.

[oh8eleven]

So to cover half, each person would need 544.5 square feet of personal space.
Thanks for doing the math - with links no less.