Which types of cables are used in PC?  

The most common cable used in PC for network or internet connection is the UTP Cat 5. UTP Stands for Unshielded twisted Pair and it consists of two tunshielded wires twisted around each other. UTP does not offer high bandwidth and better protecion from interference as compared to co axial cable & fiber optic but since it is inexpensive, it is the widely used cable for networking in the industry.

Alimentation Cable
USB Cable
Mini-USB Cable
Firewire Cable
Mini-Firewire Cable
VGA Cable
DVI Cable
Ethernet Cable (RJ45)
ADSL Cable (RJ11)
Mouse and Keyboard Cables
IDE Cable
SATA Cable
Floppy Cable
Audio Cable
Serial Cable
Com Cable
well i think i didn't forget any cable!:)

Cat-5e cable used for Networking of Computers, But there one another cable which is used in Computer networking that is Coxial Cable, Yes this also used in cable Tv connection.

cat 5 is used on networking.not in the pc.ide, sata and the power cables are used in pc.

Ok here's a little info:
Cat5 is the cable while RJ 45 is the jack you use for it.

EIDE, IDE, SATA and SATA 2 are all connectors for your drive devices to your motherboard. IDE and EIDE are the wide ones while the SATA and SATA2 are the new generation type of connectors and they are the ones that are as wide and as thin like a juicy fruit gum.

well yeah its cat 5 ! but its can be any other depends on what you use and what hardwares etc you have !!

well to explain you cat5 just have a look
Category 5 cable, commonly known as Cat 5, is an unshielded twisted pair cable type designed for high signal integrity. Category 5 has been superseded by the Category 5e specification. This type of cable is often used in structured cabling for computer networks such as Ethernet, although it is also used to carry many other signals such as basic voice services, token ring, and ATM (at up to 155 Mbit/s, over short distances).