Now that Opera is free, more and more people are turning to it as an alternative browser for IE and Firefox. As such, people will need assistance learning the ins and outs of this innately powerful browser.
Feel free to post your questions, tricks and tips, and respond to others here.
I'll try to update this post with useful tidbits as I find them.
Here are some links to get you started:
Opera 8 Wiki
Opera Feature List with Videos
30 Days to Becoming An Opera Lover
Understanding Why Opera's Screen Scaling Rocks
Shane's OperaAdFilter Ad Blocker
Why Opera over Firefox?
More Opera Advocacy (Includes links to actual benchmarks showing Opera as the fastest)
Opera Tricks & Tips
Drag n Drop Buttons to mega-extend Opera's functionality