Using this small piece of code:
Code:
<select name="test">
<?php 
for($i=0;$i<2000000;$i++)
	echo "<option value='" . $i . "'>" . $i . "</option>";
?>
</select>
It appears that Opera craps out at 32768, IE is good for at least 200,000. Don't run the above code (2 million) because it brought my machine to a screaming halt.