I'm just now outfitting my new Tenere as well. Have the awesome Rumbux bars/skid plate setup arriving tomorrow(!). Regarding the top case/pannier setup, I decided to go with the Givi Trekker Dolomiti setup. It's a new case for them, and it uses the standard Givi Monokey racks and mounting setup (with the addition of a small adapter that they include). They're aluminum, but without plastic cladding like their Outback series has (Outback also uses a special/different rack from all other Givi cases). Best part is that they're MUCH less expensive than other Givi and other quality cases, yet are still of excellent quality. No offense to anyone, but from all I've read/heard, I'd stay away from Yamaha OEM cases.
For the Givi Dolomiti, I went with their 30L top case...it's smaller than some but still gives plenty of room for overnighters and to carry tools, tire repair gear, etc. I didn't want a giant top box. This one is large enough for me, yet doesn't look out of place by itself. It stays on my bike all the time. I will be adding matching side cases soon. Again, check pricing on Revzilla, etc. for the Dolomiti line...I was shocked at how much less they cost with the quality you get.
I also installed an AltRider luggage rack. This rack increases carrying capacity greatly over the stock plastic rack, is much larger, and for about $20, they make excellent Givi Monokey top case adapters that allow my Dolomiti to easily pop on and off, yet there is ZERO movement when on the rack.