Actually a Modem is nothing but a converter hence the name (MoDulate / DEModulate). It's simply converting an analog signal to a digital signal.
Hub is an antique peice of equipment that rebroadcasts a signal on ALL ports. Hub's have been completly been replaced by switches, which only give infomation to the port that requested it.
A router passes infomation between two networks, in your case this would be your home LAN and the internet. They take one IP address you pay for and split it up.
Also just using a modem and hub would not work, with most ISP's using this configuration would only allow one computer to be online at a time.
For small home use I would recomend something like this, It's a router with a built in 4 port switch