When it comes to Drupal I love entities. Entity display modes provide simplicity in managing how your content is displayed. I used to be hardcore "Fields only" when it came to using Views and displaying content. Yeah, it gives you more control, but it is a pain in the ass when you have to replicated your field settings multiple times (if you have to.) Wouldn't it be super easy to just say "Hey Views, render this entity!" and BAM it is all there for you.
I'm going to Florida Drupal Camp, and actually proposed a session on Rockin' Responsive Content with Panels Layouts.". It looks to be a kickass camp, so get registered and go!
I gave a presentation last month at Drupal 414 on building responsive websites using the Omega framework, and compared apples to oranges with version 3 and 4.
For quite a long time I used Aptana as my development IDE; but, as time went on I found it quite bloated and extra features I didn't need. So I gave Sublime Text a try since it's all the rage by those who use it. Sublime Text is amazing because it's so simple, yet extendable. At first I was put off by a few things so I figure I'd share my setup and packages to turn Sublime Text into your IDE powerhouse!