Right bike depends on what you actually do. Not what you think you’ll do. Here’s how to choose.

Road Bikes
Paved surfaces only. Light, fast, aggressive position. Drop bars. Thin tires.
Great for fitness riding, group rides, racing. Miserable for anything off-road. Even gravel hurts.
Mountain Bikes
Off-road trails. Suspension absorbs bumps. Wide tires grip dirt. Upright position.
Heavy on pavement. Slow. But handles anything nature throws at you.
Gravel Bikes
The compromise. Drop bars like road bikes. Wider tires for unpaved surfaces. Works okay everywhere.
Not as fast on road. Not as capable off-road. But versatile enough for mixed riding.
Hybrid/Commuter
Flat bars. Comfortable position. Medium tires. Built for getting around town.
Good starter bike. Not specialized at anything but does everything adequately.
The Question
Where will you ride 80% of the time? Answer honestly. That’s your bike type.
Buying for occasional use cases is a mistake. Get what fits the regular riding, rent the exceptions.
Budget Reality
$500-800 gets you something functional. $1500+ gets you something good. Diminishing returns above $4000 for most riders.
Buy used if budget is tight. Previous generation components work fine.