Cylinder - Sexy homescreen icon animations
Springtomize - Tear down the walls
Winterboard - Give your iPhone or iPod Touch a graphical overhaul!
Five Icon Dock - Tweaks the dock of your jailbroken iPhone so that it can fit five icons instead of four.
Five Icon Switcher - This puts more icons into the iOS4 multitasking bar, instead of the usual four.
Infiniboard - Vertically scroll your home screen pages!