I was just thinking, but would slaughtering your workers to build temples early on be a viable strategy? You are capped at 6 in most of your ancient era towns regardless, and the temple itself would make the unhappy person content, then you would have the temple, and you would radiate the cultural influence early. Would the same thing work for Cathedrals? Come to think of it, unless you have contact with a lot of civs to get tech, or a lot of Rivers, most of your towns are just siting at 6 population anyway. Put those pop-points to good work I say :)

I have done that in my last two games because the sooner you build your temple, library, etc. the more culture you will have...

It seems to work great during the early game, but not so much in the later game

Absolutely, I'd say its almost critical for early expansion. While I'm doing expansion, after I get enough settlers rolling, any border city starts sacrificing lives to build temples and even libraries.

Start radiating culture on the edges to keep the AI from easily getting in.

I have also built workers at my early towns for the express purpose of sacrificing them at the border towns...

Press B when the worker is in the border town and then even if the city can't support the pop - you immediately finish off the temple or whatever...

Another good strategy with workers is to use the captured workers you get from a war with the AI to expand the newly captured city and then rush build important military units.

Interesting, I did some tests and found this works for Granarys as well. Check out my post on the Mad Skillz - Rush Build Granaries discussion