alt Hacker NewsI know when I was doing some custom wiring in a house around 2005-6, it was clear that cat-6e was the thing to use if you wanted any future-proofing.
So I bought a reel of that even though I was only going to be using 1000-BaseT. I don't remember there being too much premium on the wire itself.
Do you mean Cat 6 or Cat 5e? Cat 6e isn't a thing and 6a didn't exist in 2006. 6 was certainly more future-proof at the time, although arguably 5e is still fine even today. (Super-gigabit consumer equipment didn't really exist until the last five years and it's till notably more expensive and less common than gigabit, which runs on 5e just fine.)