The kind of kettle you should buy depends on your lifestyle.
If you love your coffee (especially pour-over), you should get a gooseneck kettle. The long, thin pour spout with a slight S-shape neck allows ultra-precision.
If you don't want to watch over your stovetop kettle while it boils, getting one with a good whistle means you can leave it while you do other things.
The Fellow Clyde Stovetop Tea Kettle even has a nice two-tone harmonic whistle so you won't be surprised by a loud screech.
If you value speed, you should choose from the best electric kettles. There are even electric gooseneck kettles!