Of course do a service before you go! How far are you going and where to? Will there be any dealers on route should you need help?
As to what to take - take what you will use. Theres no point taking loads of tools if you're not prepared to use them. Think about what jobs you are willing to tackle and are likely to occur and equip yourself accordingly.
If its a long haul then inner tubes are definately handy to have but only if you are capable of removing the tyre yourself. You will also need tyre irons and some means of inflating the tyre again. Then again if your not going too far from civilisation it may be better to leave all that stuff at home and pay someone else to fix it.
I would take the original BMW tool kit supplied with the bike, and throw it in the bin. Replace it with quality tools than can stand up to the rigours of actually being used. And add a few more that come in handy too.