I wear a size 12 shoe and when I knit my socks I make the foot about 8 5/8" and they fit me just fine (with some stretching). I would expect that a size 10 or 11 would need about an 8" - 8 1/4" foot (just a guess) before the toe.
In reality I should make the foot about 9 - 9 1/4" inches for my foot size but I hate baggy/bunchy socks.
Here's a chart that shoes shoe size and foot length conversions:
http://shoes.about.com/od/fitcomfort/a/men_inches.htm