What is the Point of Buying Stupid Routers?

Now that I've got your attention. I need help. I'm new at this. I don't know much about routers or what they are used for but I know that I wanna buy one. What exactly are they for in terms of internet usage, Will buying a different router cause problems between me and my ISP? Can I use it to link to more than one outlet such as my Laptop, Wii and Xbox 360. Will it speed up my laptop and finally, Which is the best (and peferrbly not expensive) router? Any help will be appreciate...Oh and sorry about the cynical title.