I'm a big fan of keyboards, so a lot of thing a done by combination of keys, like open a file browser, web browser etc.
Is there some daemon that can monitor my key presses, and launch some program afterwards, so that I won't have to configure anything else after moving to another desktop environment?
This might not be quite what you're looking for, but if you install dmenu and associate it to a key (so that's only one shortcut you'd need to define in any desktop manager), then you can use it to launch other programs.
dmenu presents itself as a small horizontal bar appearing on top of the screen, that will suggest completions of executables as you start typing them. For example, to launch firefox you's first press whatever key combination you mapped to dmenu (e.g. Logo-R) and then foxEnter.
I'm not sure what you're trying to do. If you want to make a key combination perform an action, you can use XBindKeys. The companion program xbindkeys_config can help define bindings. If you want to act on existing windows, invoke a program such as xdotool or wmctrl.
If you want to make a key combination simulate a sequence of key presses, try xmacro.
Give a try to diyism myboard python version: https://code.google.com/p/diyism-myboard/downloads/detail?name=myboard.py The issue in it: https://stackoverflow.com/questions/15270420/does-anyone-know-an-xlib-function-to-trap-a-keypress-event-without-losing-the-or/15404395#15404395
