In OpenBSD/FreeBSD I use OpenBox/Tint2/Wbar as described in this FreeBSD forum post.
Lightweight FreeBSD desktop howto
Wbar was my first attempt to make an OpenBSD port with significant help from Antoine Jacoutot.
Wbar is written in C++ originally for use with Fluxbox but I chose Openbox on the basis of the FreeBSD howto
I also feel that the Tint2 panel has more flexibility than the fluxbox panel. The svn version of Tint2 can be make to look and function like the Xfce4 panel complete with menu and application launchers.
My Tint2 clock will launch the calcurse calendar and my default terminal is rxvt-unicode. OpenBox/Tint2/Wbar/rxvt-unicode are all setup to use Redhat's Liberation font package.
I am looking at using the systray of tint2 to install an audio volume applet. There are several out there (gvolwheel, volumeicon, pnmixer) gvolwheel has been ported to FreeBSD using the oss backend. None of the volume applets support sndio directly.
I do not want to drift off thread on the challenges of volume control applet in OpenBSD so I'll end the post with a screenshot - the mouse is placed over the Wbar icon for the xombrero browser. Commonly used apps can also be launched from Openbox keybindings and less frequently used apps from the Openbox right-click menu.