What's the difference between MAC airport extreme and air port express?

I have Wi-Fi but I do not have internet because I need a modem.
Which air port should I get for my laptop, apple tv and iphone?

1.Both the extreme and express are Wi-Fi routers. The extreme has more capabilities, such as ethernet ports and can have a printer or harddrive hooked to it. In fact using a usb hub you can hook multiple drives or printers to it. The extreme can extend an existing network but will not provide airplay functionality.
2.Extreme has three LAN ports; Express has one (both have one WAN port)
3.Extreme has Gigabit Ethernet, Express 100-BaseT - this affects activities such as performing large file transfers or streaming
4.Extreme's USB port can be used with an external hard disk, Express can only be used for a USB printer.
5. The express can act as a router or extend an exisitng network, but will also act as an airplay node for iTunes. It has a usb port but only for connecting a printer and can't be extended with a hub.
6. Only the Express can stream iTunes music.
7. The Express is about $80 cheaper than the Extreme.