Ethernet Switch

I'm looking to purchase an ES so I can manage connections through-out my house. Unfortunately Wi-Fi is not an option(even though it is MUCH easier). Now I have a couple of questions, I hope some of you can answer a few.I browsed and saw this "10/100 MBPS". What does that mean all together?Does buying an ES slow down my speed(vs. direct connection to modem)?If the above is true, what type should I purchase(Fast Ethernet, Gigabit, etc.)(if it means anything))?

10/100 means it supports both 10BaseT ethernet and 100BaseTX fast ethernet (10mbit and 100mbit respectively) Virtually all switches should support this, although some may also support gigabit (also written as 10/100/1000). Your speeds will not be affected, latency might be increased by 1ms but that shouldnt happen.