Using checkboxes, dropdowns, radiobuttons in plugins.

I’m developing a plugin. It’s really easy to use single input fields like a textbox but when it comes to checkboxes and dropdowns which I need for my plugin I’m lost.

So this is my code for a single field:

<tr valign="top">
	<th scope="row">Height (in pixels)</th>
		<td><input style="width: 200px;" type="text" name="height" value="' . get_option('height') . '" /></td>
</tr>

Register the settings
register_setting( 'my-settings-group', 'height' );

and implementing it to a variable
$height = get_option('height');

And then I can put wherever I want. But with checkboxes and dropdowns this method doesn’t work. Any ideas of implementing checkboxes in the same level of simplicity?