I really do not like the way window resizing works in OS X. In OS X you have this tiny little place in the bottom right of each window. You have to carefully aim your mouse to grab this little thing, and then you click and drag to resize. Be careful! You might find yourself accidentally moving your mouse over the dock and then you click an application instead of the window.
Windows 7 does things a little better. You can resize a window on all 4 sides and corners. They also came up with a feature called Snap. This lets you drag a window to the top, right, left, or bottom of the screen and then the window takes up half of the screen while staying mounted to the side you dragged it to. Very handy feature. It's great for comparing two windows side by side or maybe copying information from one program into another.
There's this really nice app called BetterSnapTool on the mac app store. It is $1.99, as of this writing, and it adds Windows Snap to Mac OS X. It's worth the price of a coffee and if you often find resizing windows frustrating, this app is a god send.