My recommendation:
As a mastery rank 11 I'm still using the Boltor everywhere.
The Boltor is a very good weapon in all levels because it does constant damage regardless of the enemies armor and levels.
I think the Boltor is the best all-rounded damage dealing weapon with emphasis on damage per ammo at all levels (NOT DPS).
Regarding the bows:
I don't like bows at all so I just dumped the dread and paris as soon as I got them to 30 for mastery.
If you like bows however, based on earlier discussion in the forum I suggest that you will use the Paris Prime over normal Paris or Dread.
Regarding secondary:
I potatoed my Kunai but I sold it after I compared it to potatoed Despair.
After mastery rank 7 I got myself the Acrid and I'm using it since.
Regarding melee:
At higher levels the melee weapons become less and less useable because you just die too fast when you get hit up-close (in most warframes) so I wouldn't waste the catalyst on that.