Don't bother using Linux if your a casual PC user. Please. If you work in IT or are interested in that field then go for it. There are a lot of great tutorials and how-to's for just about every big linux distribution (we call them "Distro's"). Bad thing is if you want to run Flash (for Youtube) on Linux your stuck with a older version. Adobe stopped supporting it natively a long time ago. The workaround is easy enough, just use Google Chrome (it has a built in version)
As for using Itunes on Linux, not gonna happen. At least not on a laptop. You would have to run it in a emulator (or a Virtualbox/Virtual Machine, with Windows and that SHOULD be a legal version, not pirated.) And emulation takes a good amount of overhead.
The look and feel comes down to what you like. I personally use #! (Crunchbang Linux) because I value speed over all else.
Also good luck with video support. One of the biggest gripes I have personally is support for the Intel HD 4000-series video processors. If you use Nvidia or AMD it's normally OK.
Last thing, if you want a "complete out of box experience" meaning boot up, install the OS and run it you should look at Linux Mint. It comes pre-configured with a lot of 3rd part applications already installed. You could, of course, install them on your own under Ubuntu (don't bother, Unity has a high overhead for what it really needs to run well, plus Ubuntu has integrated Amazon now, no thank you!) So yeah, sorry for my formatting being all over the place, and good luck.
Edit: Oh and forget using Netflix on Linux, unless you run ChromOS (not sure if you can download that.) Netflix has started using HTML5 and it's DRM security but a large chunk of the library still needs Microsoft Silverlight (DRM). You can't get that easily on Linux. There are hacks and work-arounds, or you can use the virtualbox/virtual machine method I listed earlier) but the experience isn't very pleasant, at least to me. Again, good luck.