I am an ubuntu 12.04 LTS unity 2d user. Unfortunately, my computer cannot completely handle the requirements for 3d. Oh well. Anyway, I've managed to make 2d completely usable and comfortable for me (and even though I'm on the fence about unity, I've managed to work around it). But anyway, when I began using 2d I was often disappointed by the small details that make 3d ubuntu look so much better than 2d.
One of the big gripes I had with 2d (and I noticed with other distros like xubuntu), is that the panel shadow is almost always not present. Sure, there are window and menu shadows you can enable with gconf and whatnot, but these don't help create a panel shadow.
I found a way to get around this: I simply logged into 3d and took a screenshot of the desktop. I then logged back into 2d, make that screenshot my desktop background and voila! panel shadow in 2d. It is a small detail that I had always wanted in 2d. To me, it actually makes the desktop look a LOT better. To each their own, I guess.
But, I wonder, why are panel shadows always omitted in lower specc'd distros? I mean, my solution was pretty non-technical and simple. I'm sure the explanation as to why is much more complicated, but surely, someone smarter than I could write a small code to put something on the desktop background image for a panel shadow feel?