Web Development means you have to know the tools you use and love. It's mainly about code, letters and symbols. Being able to code means being able to write and read a special kind of language. And there are quite a few languages out there. So, at some point you learn to better make a decision before getting lost in your own language mashup. But you should stay open minded for new input, perhaps learn a complete new language every year. But it's definitly good to know, with which language you are most comfortable.
Yes. That where my web dev roots are. From building my first guestbook to development and maintainace of web applications. I have been doing PHP for ten years I think, and allthough using it daily, I still do not know every single possible command. I love this language. And I had plenty of conversations about _the only one_ programming language. There is so much PHP code out there, you better use your time for checking out all this stuff. I really enjoy using ZendFramework, Doctrine and PHPUnit. All are great tools written in PHP for building small to complex web apps.
It started with table markup full of elements using strange attributes. But there were people seeing the light. And at some point I saw it, too, and started using CSS for styling clean markup code. And I'm quite happy about that. Yeah, we have Internet Explorer, and we web devs had hours of pain behind us. But we are absolute clear about our goal right now. Twitter Bootstrap and the blueprint framework helped a lot and make my developer life much easier. So looking forward to columns, great typo sites and all this stuff.
SQL, CouchDB, ElasticSearch, ...
It's all about data. Sometimes big data, sometimes small data. In tables or documents. Reduced or grouped. With relations and complex structures. Perhaps it should replicate or sync, but it should definitly scale, if needed. There are pros and cons for choosing a database solution. It definitly depends on the kind of your application or tool you want to develop and the needed data structure behind it. I'm quite happy to be able to use such tools and having people developing them. But I really like seeing much movement in this area. Tools like elasticsearch or couchdb offer great new ways of accessing and storing your data.
Web Ops knowledge
I'm a developer, so mainly, I'm quite happy with things working easy and in some out-of-the-box way. So, yes, I know about Nginx, Apache, setting up Databases, install PEAR packages and using the shell. I use Vagrant to get up my development setup, but prefer having someone to know more about writing cookbooks and the server stuff. And yeah, all the cloud stuff is really awesome. But at least, I prefer developing something (and keep learning in the ops section).
So, if you're interested what I'm using and developing public right now, watch my github Account. And if you're searching for a web dev, with some PHP, ZF(2.0), Doctrine, PHPUnit experience, don't hesitate to contact me. I'm looking forward to great new projects!