Wanted to make sure you don't have the wrong impression. A displacement hull will not ever plane, no matter how much power you throw at it. It's limited to about a speed in knots of about 1.34 x the square root of its waterline length in feet. Thus a full displacement boat with a 25-foot waterline can go no faster than about 1.34 X 5, or 6.7 knots. A 50 foot waterline could get you up to only about 12 knots.
A semi-displacement boat like many "trawler" type cruisers in the 30-40-foot range may be able to go 12-16 knots, but at a major cost in fuel. They will also go 7 knots well, but not quite as efficiently as the full displacement hull.
Our 26-footer is a planing hull, with a deep-v shape, that is to say a lot of deadrise at the transom. The aft sections of the hull are largely flat fore and aft, but the hull cross section is quite v-shaped if you look at it from the rear. Deadrise is the angle from keel
to side between the horizontal and the hull bottom. Ours is 19 degrees, a moderately deep-v. So it can plane, and travel at 25 knots or more at full power. The v-shape helps it crush through the chop comfortably at planing speeds.
We most often go slow however, at 6-6.5 knots, and save a ton of money
- it uses roughly 3x as much fuel per mile at planing speeds than it does at 6.5 knots.
Chines are the point where the hull bottom turns up to become the sides. Our planing hull has hard chines, or a fairly sharp angle between bottom and side. Soft chines are more rounded. Soft chined boats can be a little more efficient at displacement (slow) speeds, all other things being equal, than hard chined ones. But chines are a minor factor compared to the basic hull types we've been discussing.
One of your key decisions will be how fast do you want to be able to go, and how much are you willing to spend to be able to do that. Another key one is how much distance will you realistically cover. We do thousands of miles every summer, so fuel cost is quite important to us.
We're happy to travel slow - it's more relaxing, and we see and appreciate more of the beauty around us on the PNW coast. If we were not retired, and had only weekends or a week or two for an outing, we might be willing to go fast more often.