In KDE 4.1, whenever you open a window, it invariably is never opened in a maximised state - something that annoys the crap out of me. While it's something of a chore, the following is how you can sort this out:
You can also visit the other tabs, especially the window tab to see how things work. While this can be made generic enough to apply to all windows, it's probably not a good idea as you do want some windows (for e.g., instant messengers) to retain the default geometry.
You can also create general rules for window behaviour by visiting System settings and the window behaviour applet within.
Hope this helps somebody out there!