If you are using a "Mighty Mouse" then a squeeze of the sides will activate Expose and reveal all open applications on the screen at the same time.
Click on the one you want and it comes to the foreground and becomes the active window.
Without MM, try hitting the F9 key, fn+F9 on the new keyboards, and the same will happen.
As mentioned in another post, there is more than one way to skin a cat.
On the subject of the Maximize button. There actually is one but it does not function in the same way as the maximize button does in Windows.
If I have a 24" screen, and am in Safari, on a Windows machine clicking the button causes the current page to fill the entire screen. Unfortunately, the page designer did not build the page to fit exactly on a 24" screen. The result is a large web page, artificially made wider, that has nothing in it. Some people like that.
In OSX, clicking the button makes Safari display the entire width of the page, as designed by the builder. If the page was built to fit on a 17" screen, the button expands, or contracts, the page to the edge of the actual page as it was originally built.
I'm not sure what the standard size for building web pages are now but it used to be that pages were designed for a 15" screen so that you could be sure that the page fitted on almost every monitor out there, without the need to scroll.
Screen sizes have moved up, so I expect that the "build to" size has increased too.
In other applications, clicking the button expands, or contracts, the window to encompass whatever is in that window. It seems like a waste of space to open a folder containing 1 item and to have that folder occupy all of the viewable screen, some people feel more comfortable doing that though. Maybe it depends on what you are used to. Apple has never had a expand to fit the screen button, neither has Windows, but I'm pretty sure it is not a conspiracy as has been suggested.