Windows 7's Aero Snap is a pretty neat feature, allowing for easy side-by-side window sizing of any application. You can get a similar effect in Ubuntu by tweaking your Compiz configuration settings.
Getting a half-size, Aero-Snap-like window when dragged to the edge of a window is easier than it might seem — assuming you've got the right commands to enter into the CompizConfig-Settings-Manager app, like the OMG! UBUNTU! blog has. Make a quick installation of Compiz's settings manager, if you haven't already, and enter the commands and variables recommended at the link. Now when you drag a window to the screen edge, you'll get a half-size window to stack up.
Two caveats apply to this trick though. One is that you seem to lose the ability to drag windows horizontally into your next workspace. The other is that, depending on how you set it up, a dual monitor setup might not give properly sized windows. I can live with the first issue, as I only use one workspace, but my TwinView setup doesn't quite fly with this trick. That said, it's a great option for laptops or single-monitor setups — and if you know of a fix for those with extended desktops, by all means, tell us about it.
Get Aero Snap in Ubuntu [OMG! UBUNTU!]