Welcome,
I would go for 'old' original Yamaha bashplate + lower engine bars. I know it very hard to get them but seems to be the best option (for me obviously).
Alternatively you can go for this :
http://www.adventure-spec.com/defaul...0z-tenere.html but its quite expensive.
Forget (again its my opinion) the high engine guards etc. (i.e. givi )
I would also look for head light protector (depends how seriuos is your off road riding) but anyway its good protection. (folding brake pedal is also worth considering- I am in the process of 'upgraiding' mineafter last spill)
Have you got standard exhaust? If so try to find something else original one is very heavy and doesn't sound good (single pipe is nice and you get some storage space where the second exhaust was).
Center stand, hmmm, again its up to you but for me (and probably most of the members here) is not necessary and, again, its extra weight. (chain lube you can do it easly on the side stand, chain adjustment - get paddock stand (24 quid) or suitable cut-to-measure timber will do

.
Try to get in touch with Kev here and ask for his recommendation regarding MOD's.
Regardning luggage its individual choice but I prefer soft luggage (I do ride solo so its easier, lighter and cheaper for me).
BTW, It might be worth checking of your regulator/rectifier has been sorted out - early Tenere models had a problem with them.
Nice bike - enjoy.