My Macbook Pro is my main machine. At the office, I connect it to a 20" Cinema display. At home, I connect it to a 24" Samsung Monitory (Model 2494SW Glossy Black, which I really like, btw.)
There's a down-side to all this, though. I mostly just notice it with iTunes. When I'm working on the laptop without an external monitor, my iTunes window is larger than my screen :( Unfortunately, clicking the Maximize button doesn't do what I want (which is to make the window fit in the screen. So here's a little Applescript to to fix it:
tell application "iTunes"
set the bounds of the first window to {50, 50, 1024, 640}
end tell
The arguments are the distance from the top and left of the screen (both 50), the width of the iTunes window (1024) followed by its height (640).
I just saved this in a file called resize_itunes.scpt and put it in my Documents/Applescripts/ folder. I'm a big fan of Quicksilver, so when I need to resize my iTunes window, I just activate Quicksilver (Ctrl+Spacebar), type in "resize" (which finds the applescript file), and then hit "enter" to run the script. Easy.