Depends on what your goals are.
Super fast riding but not long trips, some more dirt bike-oriented duo sports. Enough that you don't need to trailer it, but you won't want to spend the day just on roads with this.
Fast riding, but longer trips, one of the 700cc/800cc options are great since they are a little lighter and still semi dirt bike ish. Ktm 790/890, BMW 800gsa, Yamaha tenere 700, etc.
Longer trips but a little slower riding (heavier and harder to take to some places), a bigger 1200/1300cc bikes are great (I ride a KTM 1290 SAS). Ktm 1290 sas/sar, BMW 1250gsa, yamaha super ten, etc.