If you buy your beans already roasted but want to control how the flavor comes through then get your own grinder to regulate how coarse or fine you want the grounds to be. Course for plungers and percolators and finer for coffee makers (drip machines) and espresso machines.
Some machines have their own regulatable grinder built-in but most don't.
Generally, the tilt grinders look after the beans better than the ones with knives because they tend to bruise the beans. Beans are better when they are crushed although these machines tend to cost more because of the heavier gears used.