Longtime linux user here.
I commend your willingness to adventure, but I think the way you are approaching (i.e., using emerald with Gnome 3 or Unity) the hard way.
I've used the combination of Emerald + Compiz with a variety of DE such as Gnome 2, XFCE4 and LXDE, and while it is one way to get a pretty desktop with desktop effects, it is much easier nowadays to just tweak around with some of the more full-featureed DE such as KDE, Gnome 3, or Unity. Specifically, I think it a pain how you have to configure compiz to autostart and then have to tell compiz to use emerald as the windows manager. Second, emerald is not really actively developed anymore, and the selection of designs is kind of limited.
If you are using Gnome 3, you have a ton of options to configure your desktop using the Gnome Tweak Tool. There are a lot of a Gnome Shell themes out there, and many new ones are being created. You should have plenty of options to configure a pretty desktop. Even better, Gnome3's desktop effects are a lot easier to manage than compiz or compiz+emerald.
However, I think you would be most impressed moving to KDE. Hands down, KDE is the most customizable DE. It's Kwin desktop manager is more customizable and stable than compiz, and it runs better on older hardware. KDE is much more flexible for doing thing such as creating multiple desktops, each with different icons and different wallpapers. The last one is tough to do with Gnome3 and Unity. So yeah, I would recommend try out a KDE distro like Kubuntu.