I carry five.
Two Blend Judges for putting; I carry two in case one gets lost off a rollaway or something, or if I don't want to mark a lie or one gets wet from dew off a miss. I also will sometimes switch midround if I'm having a bad putting day...it's only superstitious if it doesn't work :|
One Lucid Judge for straight to understable upshots and drives, handy dandy disc for working weird angles or straight at it drives.
Two Harps; one VIP and one BT Medium. The VIP is the one I mainly drive with; really super dependable in the wind and on a normal shot, can get some good flew lines too. I'll also throw this for upshots where I want a lot of skip. The BT is more for a forwards fading overstable upshot and upshots where I want the disc to sit and not skip as much. Even though the Harp is like a glideless brick (although there is actually some glide after the fade believe it or not), the BT Medium feels like it gets some good glide forwards.
I also want to make a side note: the Envy is a great throwing putter. I bagged one for a while but between it, my Harps, and my Roc3, there was too much overlap, so I took the Envy out because I can do a lot more with my Roc3 and Harp pair than just an Envy.