I agree. I almost always put semicolons after my looping statements. Luckily, compilers are smart enough to tell me just how brain dead I am for making the same typing mistake about 50 times in my program. However, my biggest problem isn't the dread one character error problem. I usually rename my variables accidentally in my head, and it usually takes me hours to figure out exactly what it was that I did wrong.

For example, in Perl (note that the variables are usually not on the same screen):
$num_to_start = 5;
while ($num_to_start)
{
print $number_to_start++;
}