Just a quick suggestion today - if you haven't already done so, I'd recommend checking out the success stories section of drupal.org.
Basically it's a collection of write-ups by people who have built some bigger sites using Drupal, and the processes they went through, modules they used etc. Obviously some are better than others, but I think they're all well worth a read, both for techniques and inspiration.
The most heavily commented of the lot is The New York Observer write-up, a very well written article (no surprise ;) ) which highlights some impressive usage of CCK theming, a tabbed box module, and flash integration. Interesting stuff.