When it comes to charging for my services as a front-end developer I always charge a daily rate. I've never heard of anyone charging an hourly rate in this business. I'm from the UK, so maybe it's just the way we do things here. My daily rate on average is £120, that's about $236.50, for this type of work.

When it comes to semantic XHTML/CSS design I have to agree with most of what's been said here. But... Images have their place in XHTML for displaying images, as do tables for tabular data. I've seen a lot of developers completely strip everything out of the XHTML page unnecessarily. For example header, bold, italics, and even paragraph tags, just so they can later define them again in the CSS file. Get a grip people, you've taken it too far! Tags have their purpose.

I also agree with Julian that you have to build overheads in to your rates. One thing that Julian missed is including something for the days that we don't work. Being freelance we can't possibly work every day so we have to make up for this. All things accounted for, this is why our daily rate is higher than a full time member of staff.