Leaning html and css together would be a good practise. I personally program in php as I am a c/c++ coder and php is based on c so if you have prior experiance you may find you have a bit of an advantage. Java / AJAX i would then suggest as your next move but as things are constantly changing it is important to stay upto date with the latest trends.

I agree with Omol. But it depends a bit on what you would like to do with the knowledge. With Javascript you can do a lot of things, just for a "basic" website. But if you want to work with databases that I would suggest PHP. You can do a lot with both, so I guess it's important to learn them, but prior experience goes for PHP and Javascript. In which you have the most experience determines (I think) which language you should learn first...

A good website for learning all kind of languages and terms is: http://www.w3schools.com/

Hope this helps!

I would suggest first learning CSS. It has become a web standard for styling HTML text, images, etc. Once you have a very good understanding of CSS (It's pretty important to know it!!!), I would suggest going on to JavaScript. If you are creating forms you will want to have code to validate the fields before the server is sent the request. Lots of other elements require JavaScript such as FAQ's with Show/Hide Toggle Buttons, Fading Effects, and other tasks that can be accomplished from the user's browser.
After you have a very good understanding of the basics (HTML, CSS, and JavaScript), then you can go on to a more advanced server-side language such as PHP. I am mainly a PHP programmer so I would definitely suggest PHP. It has easy access to SQL databases which you will find very useful from user accounts to creating a simple polling script. All of the server side languages are great it just depends on what you want to get accomplished and what the capacity of your server is. Whatever your decision, I would recommend W3Schools as a great source for learning these languages.
Since server-side languages aren't interpreted with the user's browser, you will need a server to practice with server-side code. Instead of getting free hosting somewhere and having to upload the file every time you save, you can get XAMPP. It is a server that runs on your personal computer and supports Apache (HTML) and PHP and is a great way to test PHP code!!
Good Luck with Programming!!

I'm in pretty much the same boat, except that I am familier with CSS, My next move in the web dev world will likely be either asp.NET or PHP, I would prefer to learn PHP but companies tend to like .NET (esp asp).

I would take your pick of those, and perhaps javascript.