Setting up an automation system in your house requires 3 different areas:
1) Controlled "appliances"
2) A hub
3) A controller
I am being specifically vague when I say controlled appliances because this group is vast and varried. You can have smart light bulbs, smart light switches, smart wall outlets, smart thermostats, various sensors, security cameras, and the list goes on and on.
All of these appliances will have a communication system such as z-wave or wifi that allows it to connect to the hub and be controlled virtually.
These can be extremely expensive, but most have gotten relatively cheap. For instance, the light switches I have are about $40 each. So, for about $40 per room you can completely automate the lights of your entire house.
The Hub is simply a device that connects to all of the above appliances and allows you to control them virtually. I have a smartthigns hub. I really like it, but there are several other options that you can use. All have their benefits and drawbacks.
As said above, the main job of the hub is to be the connection/control point for all of your appliances. The secondary bit is that each hub has a control OS that you interface with as a controller for your system. This will take two forms. First form is an app you can install on a tablet or smartphone that will allow you to set up routines or directly control every single connected appliance from wherever you are in the world. The second form (not on every hub) is a simple programming interface that gives you powerful customizing options to how you want to control your system. If you can imagine it (and code it) you can do it, pretty much.
The controller group is also where the echo fits in. You don't need an echo, but it is an amazing addition. Typically having a smart system just meant you could control everything on cool customized timers, virtually from everywhere in the world, and from a centralized "remote" in your house instead of having to go to each device. With the echo you can skip the tablet "remote" all together and just speak to your house and it listens.
I highly recommend diving into the world of an automated system. It is only a couple hundred dollars to get started and you can slowly build your system out over time. Check out /r/homeautomation for some more info too.
I use this in each of my bathrooms to turn on/off the lights and fans. Comes on instantly when they see motion.
http://www.amazon.com/gp/product/B00KCYD9PC
You can also buy Wink hub
http://www.amazon.com/Wink-PWHUB-WH17-Connected-Home-Hub/dp/B00PV6GAI4/
or SmartThings hub
http://www.amazon.com/Samsung-SmartThings-Hub-2nd-Generation/dp/B010NZV0GE/
along with a motion sensor. You can then set it up to turn on/off when you enter/leave your house and/or enter/leave a room. You can even set it up to slowly turn on the lights in your bedroom at a certain time to help wake up. There might be a delay with Wink or Smarthings of up to 5 seconds.
Edit: Just noticed you mentioned false positives with pets and motion detection. You should be able to set the motion detection levels so that your pets don't activate the motion sensor. I have a motion sensor for my alarm and it's set enough so that it sees me move, but not my dogs. I haven't had the motion sensors for my lights in the bathrooms go off from the dogs, but my dogs don't go into any of the bathrooms much.
I'd go with the following due to their ease of use & all the expandability doors that will open as a result: