There are a number of factors with installing an in-ceiling system. First for the sound to relate to the picture, the picture needs to be high on the wall, such as a TV over fireplace or projector screen mounted on the ceiling.
Second, and this is a big one. For speakers to sound their best they need to aim in the direction of the listeners. Most ceiling speakers do not do come close to this. The inexpensive ones tilt slightly about 15 degrees but not enough to give good sound in the listening area. Here is some math to help.
We'll start with your head being ~4.5ft off the ground when seated with 8 foot ceiling. For the example let's say you sit 10 feet from your TV and the speakers are above the TV. The speakers would have to be angled 70 degrees to be aimed at the listener's head. The speaker that tilts 15 degrees is not a great choice for this situation but this is what most inexpensive ceiling speakers are.
Now what about the dispersion of the speaker. A good speaker will still have a good frequency response +/- 30 degrees or more of axis. So narrow your search to speakers that angle ~40 degrees and your likely to get something that sounds a LOT better for this application.
Some brands that have these speakers Triad, Episode, Snell (now out of business, but some closeout pricing might still be found), Definitive Technology, Infinity, JBL, Thiel on ceiling speakers, and I'm sure I am missing some.
To get even better sound it is good to look for an in-ceiling speakers that are built into an encloseure. Speakers sound different depending on the amount of space behind them, so many of the open back speakers might not sound the greatest if they weren't designed for the approximate cavity space they will be placed. This is true of in-wall speakers as well.
The least expensive in-ceiling LCR speaker that I know of which has a decent angle is about $450 each MSRP, street price might be a little less. I'm not sure if this is breaking the bank for the original poster. If this is more than one wants to spend another solution might be better choice. Possibly an LCR speaker bar for the front 3 speakers, or possibly in-wall or on-wall speakers around your display. You could use some inexpensive open back in-ceiling speakers for surrounds if budget is tight. The surrounds aren't as critical as little dialogue comes from them. Some dual tweeter models can often work good for surrounds.
Hope this helps.