If you've decided that GNOME 3 is not for you, what do you do?
The first thing you should do is make sure that you are not just reacting against the fact that you are facing a new desktop. The fact that many people the exact percentage is uncertain -- like or tolerate GNOME 3 should be proof enough that you should be wary of snap judgments. Persist with GNOME 3 for a week, and you may find it more endurable than you originally imagined, especially if you learn how to change the default settings.
But if you are determined to avoid GNOME 3, what are the odds that you will find something to your liking? Probably, you will have to endure some differences. But assuming what you want is a desktop that resembles GNOME 2 as closely as possible, here are some possibilities to consider:
Considering the troubled relationship between Ubuntu and GNOME, Unity might be considered Ubuntu's answer to GNOME 3.
Like GNOME 3, Unity is a modern rethinking of the traditional desktop informed by the standards of mobile interfaces, and requires hardware acceleration. However, where GNOME 3 gives the impression of added complexity, Unity creates the impression of greater simplicity. But on closer examination, this impression is misleading -- Unity does not simplify so much as hide complexity in its depths.
The biggest drawback to Unity is that it is another large departure from the classic GNOME desktop. If what you want is an interface as close to that of the GNOME 2 series as possible, then Unity is probably no more for you than GNOME 3.
Enlightenment began as a window manager, but is now closer to being a desktop. It has fallen out of favor in recent years, largely because its latest release is entering its second decade of development, but remains popular in some circles. Its packages are available in several major distributions, including Fedora and Ubuntu.
Enlightenment's desktop has a generic resemblance to the GNOME 2 series, and has a full set of customization settings and virtual workspaces. So long as your distribution of choice continues to offer the packages, Enlightenment is well-worth considering as an alternative.
The Lightweight X11 Desktop Environment (LXDE) provides an interface with all the features you expect, including a menu, panel, icons on the desktop, and an array of customization options. Major distributions include it as an alternative, and you can select it while logging in.
LXDE's greatest strength is its no-nonsense approach and speed. Its greatest weakness is a lack of anything except the most basic panel applets. In other words, LXDE includes a task bar and a pager for switching virtual desktops, but not a note utility like Tomboy or a wide selection of clocks.
KDE 4 and Trinity KDE
Traditionally, KDE has been the first choice for those who are looking for an alternative to GNOME. That remains broadly true, but the KDE 4 release series has a set of innovations that, if anything, are even more radical than GNOME 3's, including such things as containments (shells for a workspace) and Folder Views (collections of icons that can be swapped in and out).
By setting a Folder View to cover the entire screen, you get a desktop experience very similar to that of the GNOME 2 series. However, I suspect that anyone impatient with GNOME 3 is unlikely to satisfied with the latest KDE.
Instead, you might try a Trinity KDE, a project that begins with the KDE 3 series. Trinity KDE provides packages for Debian, Ubuntu, and Slackware, and offers a classic desktop experience that requires little, if any learning.