WM5torage acts a virtual memory card reader, letting your Windows Mobile phone's memory card appear as a normal USB memory stick to your PC, making copying files to and from it incredibly easy.
Pocket Digital Clock by Ionized
Pocket Digital Clock is a simple, customizable clock for your Today screen, without any unnecessary bloat.
MyMobileR by MTUX
MyMobileR works like Remote Desktop/VNC, allowing you to control your Windows Mobile phone from your PC, letting you to use your computer's keyboard and mouse to control applications on your phone, as well as supporting copying and pasting between phone and PC.
Nitrogen by Microfi
Nitrogen is my favourite music player for Windows Mobile. It's interface is easy to navigate using just your fingers, and the program itself is lightweight and basically just does what it says on the tin: plays music.