A combination of habit and the use of hyphens has led me to really enjoying the use of lowercase naming.
Using a hyphen provided for a solid foundation for my website design skills because it's just easier to read. Before that I was switching between upper and lower case names constantly.
Uppercase first letter of words and the rest lowercase
In the VB world it's a great way to make reading things easier because hyphens and spaces are not permitted. Examples of this would be modThisIsATest and clsId.
When working in .html files, or any website file type, always use the default file, that way if you ever switch to another extension, the paths will be valid.
I name the file the same as the class name, it just makes things easier.