What are the best resources online to learn Web design or Web development from scratch ?

Don't focus on just the latest techniques, trends, and styles; learn and understand the basics of design. Here's a good place to start: http://www.andyrutledge.com/gestalt-principles-1-figure-ground-relationship.php.

http://www.css-tricks.com. His screencasts are great, and there is a forum as well (I've never used it, though - so I am not sure how good it is for beginners). http://css-tricks.com/video-screencasts/58-html-css-the-very-basics/ might be a good screencast to start with. http://net.tutsplus.com/ also has some good material.

Lynda.com is a great resource for tutorials/instruction.

http://htmldog.com/ will teach you modern XHTML and CSS.

If anyone points you to W3 Schools, show them http://w3fools.com/. Seconding Chris Coyier and HTML Dog. Roger Johansson at http://www.456bereastreet.com/ regularly has some great articles, especially on accessibility as do the teams at http://www.alistapart.com/ and http://www.smashingmagazine.com/ (the comments at the latter are generally less useful though). A couple of other sites for your feed: http://www.noupe.com/ and http://sixrevisions.com/.

Rather than add to this already phenomenal list of resources, I just want to give a few notes about what you will likely encounter along the way... 1. Sites trying to sell you something. Lynda.com is about the only one out there that I'd consider worthwhile (although I know people who may or may not have pirated their videos...). The best part about learning web design is that if you are looking to learn something about it, odds are you can find anything you need online for free and with good quality of content. If you can't, there are great sites to ask your questions on. 2. Becoming overwhelmed. You'll learn pretty quickly that HTML and CSS are not going to cut it for "the latest techniques" you are looking to learn. The web is now a convoluted mess of languages that all have their appropriate uses. I had a working knowledge of HTML a couple years ago and didn't know anything else. I decided to get my skills "current" for my own projects, and it was a major journey to get where I am and I'm STILL not there. If you want some shortcuts to creating great sites, depending on the type of site, pick a CMS (like Wordpress) and become very comfortable with it. Once you pick up some basic HTML and CSS, and then some PHP and MySQL, you should be able to hack together just about any kind of site you need. A bonus is that the big CMS's out there have HUGE helpful communities for support, and free plugins for just about anything you could want to do. 3. Good web design also means good graphic design. Don't forget to brush up on your general design skills. Being able to photoshop a nice layout, and then code it, is a great skill to have. Plus, you'll find that some cool web design techniques require very specific types of graphics for them (think advanced CSS techniques). 4. Think hard about why you are embarking on this journey. I don't say all of this to discourage you, but I advise you to do some deep thinking on what you really want to get out of this. In my case, I am an affiliate (and as of last night proud owner of an ecommerce site) and so creating awesome sites and marketing them online is how I make money. At a certain point, depending on what I want to do, it is cheaper to just outsource the design/development. However knowing the bit of coding I do and being able to do my own design in Photoshop has saved me a fortune and allowed me to hack together just about anything I have needed thus far. There are still some very advanced ideas I have that are far beyond my reach, and I recognize that to get to the point where I can do that, I really need a lot of general computer science knowledge (algorithms and such) which is likely more than I want to get into. So recognize your true goals and your limitations. Learning something new is never a bad thing, but if you are doing this for profit, you may find a point where it just makes more business sense to outsource. 5. Don't disregard good content. If you have any aspirations of getting people to actually visit your site (which you may not if its purely a personal project thing), you need to rank well in search engines or pay for traffic. Ranking well in search engines requires three key things: relevant content, backlinks from authoritative/trusted sites, and a well-optimized site (SEO, which is a whole different rabbit hole to go down). Good luck on your journey. It may be a long one, but it is definitely worthwhile.

I've really enjoyed the Head First series. They're packed full of information presented as concisely as possible. I often have to get up to speed on various technologies at work and I no longer have the patience for text heavy 3 pound bibles anymore. The Head First books get straight to the point, have a fun and informative visual style and plenty of examples. After all, it's faster for our brains to process pictures than to read a paragraph. I'd say start with http://www.amazon.com/exec/obidos/ASIN/0596520301/metafilter-20/ref=nosim/ and http://www.amazon.com/exec/obidos/ASIN/059610197X/metafilter-20/ref=nosim/ to get the basics down. They also have a host of other books covering other web technologies. Good luck and have fun!

Sorry, I seem to have deleted the first part of my reply which recommended thehttp://products.sitepoint.com/. The http://courses.sitepoint.com/css-live is especially good and a steal at $9.95.

The rhetorically titled http://freelancefolder.com/can-you-teach-yourself-web-design/ includes some resources on where to start.