RaMMichaeL’s excellent 7+ Taskbar Tweaker has been updated to version 4.4 with the inclusion of even more tweaks and customizations. A new "Hide the Start button" option does exactly what you’d expect, for instance, saving useful taskbar space. And yes, it works in Windows 7 and Windows 8.1.
If you need another way to launch the Start menu or Start screen, then good news: install 7+ Taskbar Tweaker 4.4 and double or middle-clicking empty taskbar space will do just that.
If you’ve only used 7+ Taskbar Tweaker casually before, you might be interested in the new Advanced Options Editor (right-click the system tray icon, select Advanced Options). This provides easy access to all kinds of low-level tweaks, previously only available via the Registry. Their names aren’t exactly intuitive ("fix_hang_reposition", anyone?), but fortunately that’s not a problem -- just click Help for details on what it all means.
The extremely configurable "Mouse Button Control" feature has gained the ability to show thumbnail previews when you carry out your chosen mouse action (Ctrl+Shift+Middle Click, say, or whatever else suits your needs).
There are assorted bug fixes, too. And of course 7+ Taskbar Tweaker 4.4 includes all of its previous settings, so allowing you to customize the taskbar in just about any way you like.