I ran Cat5e 12 years ago and haven’t kept up with Cat6 so unsure if its worth the cost difference. I will say that all the various baluns for VGA and HDMI I have purchased support Cat5e. I recommend running it everywhere you think you will need it, and run a few extra runs from behind your TVs to your media cabinet since you can convert Cat cable into other types of cables via baluns.
In regards to PVC getting expensive, not really sure I follow. Local box stores sell PVC pipes for a few bucks. Here is an example of what I did during a recent addition where I installed a flat panel TV on the wall in a bedroom:
Now let me stress the importance of this… Code in my area requires the vertical boards you see pictured for ceilings 9 feet and higher. Without that PVC conduit, its extremely difficult to run wires up into the wall, hence why I suggest running PVC to any area you plan to have a bunch of wires.
I also suggest a large, 2", PVC from your basement to your attic. I cut the cord last year and am very thankful I did that because I installed a digital antenna in my attic. I had to run a wire from my media closet on my first floor to my attic and without my PVC conduit that wouldn’t have been possible. When I wired my master addition, picture above, I didn’t run Coax to that TV since I had HDMI. But after cutting the cord, I needed to get the antenna signal to that TV, that conduit made it a breeze. If you piddle like me and keep up with technology, its important to “future proof” your house by making it easy to run wires. Hopefully you understand my point. I’d also suggest checking with your builder to see if you can do some of this yourself and save cash. I did all the low voltage wiring in my addition that included security hard wired sensors, speakers, and media wires.
I purchased a Aeon Multisensor 6 from @TheSmartestHouse that is installed in a ceiling recessor. Its been working fine and I use its motion to also turn lights off as well.