You're setting the width to 110px but you're also adding padding onto the button which will make it longer (122px?) by the looks of it.
do,
Code:
#nav a {
float: left;
height: 35px;
line-height: 32px;
padding: 0 0 0 10px;
width: 100px;
text-transform: uppercase;
}
ps: you shouldn't use set width on navigation items, especially for people that don't have hardware acceleration (if someone zooms in more then once the text will be bigger then the button itself.)
And yes people do it.