You need to buy outdoor rated coax and network cable, since buried conduit is still considered a wet location.
I would run 2 RG-58 (or similar) COAX cables. The reasoning is that you normally need one cable for inbound (from cable company, antenna, etc.), and may need one (or more) for outbound to another device. For example you could run a camera in the garage and feed the output back to a security system in the house.
The cable components in many structured media boxes are just multi-port splitters. Since I doubt you plan to put a lot of TVs in your garage, you may not need any device to split out cable. However, you may need an amplifier on the house end if you have a long run of cable.
I would run a minimum of 2 cat5 or cat6 cables for your network. Wi-fi might work to your garage, but streaming or running backups is much better over a wired connection. In the garage I would use a network module (has multiple RG-11 jacks, looks similar to phone company punch-down module) to cover any connection needs in the garage. Most modules start out with 6 jacks, which is probably more than you need.
You will also need a network switch (better than a router) in the garage, if you have multiple connections. Wired switches are quite cheap these days, but I would use a wireless switch with four hard-wire connections to cover both wired and wireless. Some switches allow you configure them to separate streaming data (watching Netflix or Amazon Prime?) from your other network traffic, using virtual LANs (VLANs) or by using Quality of Service (QoS) settings for certain ports.
Its also a good idea to pull one cat5 or cat6 cable for a telephone connection, just in case you need it later. In the meantime, there are more and more devices that can distribute signal over cat5/6, so you may find other uses for it. For example, AT&T uVerse can send your cable signal over cat5.
You may want to look at the structured media panels from Leviton (and other companies). Some are preconfigured with phone/internet/cable components, while others are just a shell that allows you to add the wiring components.
Bruce