is there a way to get firefox to display more than one tab at the same time? It'd come handy if I could have two pages open side by side, especially with a widescreen monitor. Can this be done in a single firefox instance or do I have to open two instances and place them next to each other?
Try the "split browser extension".
You can split browser infinitely, as many as your RAM and your screen allow. Enjoy split and split to your heart's content!
Drag and drop is available to load links, bookmarks, and so on, into split browser. If you drag the toolbar of split browser, you can load the page in another split browser.
Split browsers can be closed by their closebox. "File" > "Close All Split Browser" closes all of them at once.