Dryrider-in addition to some very good advice others have given, you over rate the delay that your doors/windows will give you until an intruder is close enough to strike.
Depending upon house layout and where you happen to be at the time of entry, an intruder may be as close as 3 seconds to you. If you watched the Supreme Court proceedings on the DC weapons law, you saw/heard Chief Justice Roberts go through the procedure under DC law: hear noise, sit up in bed, turn on the lamp, get the reading glasses to see the lock.......... If the Supreme Court felt that requiring a defensive firearm to be locked up was unreasonable, that's a clue!
You do, however, have a point. A ready weapon must always, invariably be safely secured if it's out of your immediate control. This is why many carry the weapon within the home.