You normally put your most favorite progams by pinning the icons onto the Windows 7 taskbar. You can quickly launch this programs by using the Windows key + <Number> combo keystroke.

For example, press Windows + 1 will launch your first program in the taskbar, Windows + 2 will launch your second program that is in the taskbar.

In the example below, #1 program is Internet Explorer, #2 is the outlook, #3 is Opera browser, #4 is Chrome browse. If I press the keys Windows + 3, then Opera browser will be launched.