solid hardwood is usually ur best bet.
although u can spend ALOT more on it, a good floor can be purchased for around $3-$4/ sq ft. & installation usually runs another $1-$2/sq ft. (home depot is very competitively priced for wood). Solid wood will last 100 years , & can always be refinished for a minimal cost to make it look new again. Oak holds up the best for the price & can be purchased in different qualities for different prices, just look over several samples before u make a purchase- cause sometimes a sales person shows u the best sample as where some grades may have minor knots/inconsistancies.
The next best thing to solid wood is engineered wood- which is actually a very thin layer of real solid wood on top of pressed board, they hold up as well & cost around 25% less on average, & can even be refinished or renewed usually once, maybe twice with light use.
As for all these laminate style floors that look like wood- I would never recommend them for the price difference, all it is is a fancy vinyl tile on top of particle board, & yes i know alot of people r happy with their pergo- but ask them again in a few years, because those flooring options just dont hold up , & when they r scratched - u throw them away because they can never be refinished, also no matter what the great warranty on these is - they almost never actually honor that warranty because theres tons of loop holes to it. My boyfreind installed tons of these professionally & after a few years had tons of unhappy customers that thought they had a 10 yr warranty, well he replaced the floors on his own dollar to keep a happy customer & almost went bankrupt because of it. I dont care how much u spend on a laminate - its garbage.