John Gruber gave great advise back in 2010. If you want to avoid the use of flash or going to a second browser (Chrome) for flash use, adding a shortcut that disguises Safari on OS X as mobile Safari comes in handy.
Note: In Lion the Menu Item’s name changed. It’s ‘Safari iOS 5.1 — iPad’ now. Besides that, Gruber’s piece is still accurate.
I was browsing this review on The Verge, and the video didn’t load. An experience inferior to browsing the same article on the iPad. Then, I remembered Gruber mentioning that situation and his workaround on an old episode of The Talk Show. Now, Shift+Cmd+M reloads the site and serves video without the need of Flash. That really should be the default. But since Android dropped Flash in 4.0, it’s even more obvious that we’re getting there.