I've just finished reading building scalable web sites by Cal Henderson the architect of Flickr. And, if you're building web applications, I'd suggest that you do the same, it's a great and very useful read.

I started reading the book out-of-order, thinking that I knew most of this stuff already. But even if you've built a few solid web applications already, the book is full of wisdom and very worth reading - after a few chapters I went back to cover-to-cover mode to make sure I wouldn't miss anything.

Cal's backdrop is LAMP, but the techniques explained are valid in all environments. I especially like his focus on monitoring, measuring and relentlessy exploring to find out what's going on inside instead of relying on your gut feelings. We all know that, but some mental hammering of these principles is always good.

Cal's concrete examples can also help in convincing your colleagues of the benefits of constant measurement and monitoring.

Now, has anyone got a biiiiig system to build so that we can try that in a real setting? ;-)