I have been playing with virtual box for quite a while now, it gives me the freedom to do the mundane official task such as checking emails, writing design document, updating the xls, status reports etc where I can not get away using MS, at the same to be connected to the linux world through ubuntu. I used to switch between virtual box and window using alt + tab and then host key + F to get into full screen mode, even though I kind of got used to it, switching back and forth took lot of time and I felt I was doing remote desktop instead of running virtual box, which is hosted right at my desktop. Today morning I accidentally pressed on the seamless without realizing what I was doing, the next thing I experienced is pure nirvana... now I don't need to switch between windows and linux ...instead linux taskbar comes and sits on top of my windows desktop background and linux terminal is opened right as if I have opened a text pad. Now I can copy code back and forth from text file to terminal mode ( I agree I could do this before as well) without going through number of key presses... To one caveat is to enable seamless mode you need to have the guest additions software installed on your Guest OS
