I can't stand the default menu Ubuntu comes with and I only keep it because I have to know under which submenu the user can find an installed application when posting on WebUpd8. This wouldn't be needed if people used a menu with a search function but anyway. Also, since I install quite a few applications, half of it requires scrolling and makes it almost unusable.
From what I've seen, some are fans of Cardapio, some prefer MintMenu and forks of the Slab menu and so on. These are all great as long as you have a decent GTK theme as they don't support custom themes. Even though some might not agree, I for one prefer GnoMenu. But not using the default theme nor any theme which comes with GnoMenu but another theme from the 5 I'm about to post below.
So here is a selection of GnoMenu themes I really like and are probably among the best created so far:
1. Dark Candy
2. Icon Menu v2
3. Elemental Avio
This tiny GnoMenu theme is great for a netbook or laptop.
To install a GnoMenu theme that comes in a .tar.gz file, simply go to the GnoMenu options and on the Themes tab, click on "Install", browse for the .tar.gz file and that's it.
To install the Elemental Avio GnoMenu theme which comes in a zip package, extract the archive contents and a .tar.gz archive should be available - you can then install it like any GnoMenu theme, as explained above.