You Ask/You Answer: Luggage

Whatever you do try to remember first that your bike has a maximum kerb weight and full loaded you might be exceeding that, thus possibly making your bike more dangerous.  increasing tyre pressure is obviously necessary when fully loaded.Check spokes if you have them to make sure they are tight and correct. a friend of mine had a spoke wheel collapse on him and his missus.   he should have sent his missus by coach.

  Alterations of spring suspension will probably be required also so you might have to aletr the usual set up you have for power riding [ thats anything over 70 mph]

Try and keep the weight between the triangle made of the two axles front and back and the top of your helmet.  This usually doesnt include some rear boxes and side panniers unless the bike may be made with them or  for them as in a sports tourer. a standard bike frame is somewhat different and will be  lighter  and therefore soft luggage carriers may be the thing.

Do not overload any  backpack as that is going to hurt, after a few miles. try putting everyday things in a tank bag so the are easire to get at and move around durimng the day.

I've got some Krauser hard-luggage that is solid, waterpoof and tough.  The rack is also not too ugly when the luggage is off.

A top box is always handy for locking away lids etc (good as a pillion back rest too).  You can always start with a top-box and add hard luggage later.  Hard luggage is less likely to flop about and is more secure, but might not hold as much and will cost more.

I guess it's really down to what you'll be doing.  Just you going away for a weekend, or epic trans-continental journeys?