I'd suggest an Ecobee over a Nest, but we take advantage of some of the humidity-related controls that Ecobee has that Nest didn't offer.
Conduit, conduit, conduit everywhere. Especially since most of your houses over in Texas are built slab on grade and you can't quickly and easily run new wire through the crawlspace. And make it big conduit, things like HDMI cables have a much bigger end than cable and your longer runs of the higher quality stuff are pretty thick/stiff to begin with. Don't use 90 degree angles anywhere, there are elbows with a wider bend radius that are a whole lot easier to pass cable through.
A central media closet makes it a lot easier to control everything. It's one of the best decisions we made. The antenna and cable modem come in, inside is the cable modem, router, two desktops, receiver + stereo equipment and game systems. Coming out are all audio channels (prewire these AND use the right gage wire for the length of your run), HDMI to the tv in our family room (ARC, so it's a single cable run). Extremely simple for now, but we have the capability to run network cable or anything else if we choose to any other point in the house because of that 3" pipe running up to the attic and down tot he crawlspace.
If you're doing cameras it's also a good place to put the DVR. I'd recommend running conduit to each camera location but to each their own. I've run into wireless interference issues and keeping things wired helps control that.
More about media closets - it may help if you upgrade your current receiver to something with multiple HDMI inputs. We bought an Onkyo TX-NR757 and all game systems + PC run to that with the single cable I mentioned to the TV. It's basically our system selector (set the TV to 'Receiver', select whichever system you want with the receiver remote), and it also handles older stuff (XBox, PS2, GameCube) that run on Composite input. All this stuff is installed on wireframe shelving and has a dedicated circuit to a bank of 8 outlets behind it.
Smart bulbs, switches and whatnot aren't there yet IMO so we didn't bother with this. I find a lot of the home automation stuff to be a mess and the systems that take care of the entire house like what Lutron makes were very expensive when I priced them out. There are a lot of different providers for thermostats, lighting, doorbells, ... but none of them talk to any kind of simplified, centralized control yet as far as I know. Maybe in 5-10 years something will come along but I'd imagine it would require new hardware.