AberdeenBikers

Depends on whether you are a Gurlie Gurl or someone who can get by with the bare essentials, Expandable tank bag with magnets and a tail pack should do you for a few days, Oxford do some good ones.

Soap bag, 3 x pair of socks, 3 x skiddies, 3 x T-shirts, a fleece, a pair of jeans and a pair of trainers is what most guys would pack for a 3 day trip.
I take a first aid kit as well, lots of Nurofen plus for stiff legs or back and good for hangover too.

If you are travelling light, one each of the above and a credit card, bin the dirty stuff as you go.

Using a back pack can be very tiring on long trips on twisty roads so keep the load in them light, don't forget your waterproofs, keep them handy, pack them last.

Hope this helps.
Izz,

I always prefer a tailpack, I find a tankbag gets in the way a bit.

Whatever you choose, make sure it's got plenty of straps and / or bungees built into it. I had an Oxford tailpack that had a thick velcro strap you could secure under the pillion seat and a couple of bungees that went diagonally from corner to corner. Very secure and much less faffing around than having to come up with my own way of securing it.

Tail pack gets my vote

Much less intrusive when riding

Tank bag preferred here. You getting the picture yet? It's all about what suits you personally. I found a tailbag interferes with the feel of the bike more the more it's loaded, and I don't really trust them anyway - too many horror stories about them coming loose. If the tankbag doesn't impede your riding position then you will barely notice it... much easier to take off/put on too if you have a metal tank - no straps required! For weekend trips, it should suffice. IMHO, YMMV - of course.

Used a huge expandable Oxford tankbag on the GS for the trip and it was great. Used an expandable tail-pack (also Oxford) on the 'Gay Blade. That worked well too.

You can get the Oxford stuff through eBay sellers really cheaply too.

On a sportsbike the tankbag might get in the way depending on the riding position. As Izz says - a rucksack is poor for longer trips.

I have one of the tank bags they sell in Lidl every so often and it is useful but it has scratched the tank a bit. I think this is my fault for taking it off and putting it on the ground. It picks up bits of grit off the ground then they are between the bag and tank when it goes back on I find it quite difficult to get a rucksack onto my back when wearing my armoured jacket as the straps won't go past the shoulder armour bits.

What you want is a nice top box mate! You know it makes sence.