Psychic:
+ Not covered by CAP before
+ Not SR weak
+ Draws Ghost attacks
- Draws Persuiters
- Bad STAB in OU due to the rampart Steels
- Can't do much on the physical side of things, with only choices of Psycho Cut and Zen Headbutt for physical Psychic moves, and therefor, might find beating the blob and Tyranitar difficult. Especially as the latter is immune to it's STAB.
- Dosen't take any of Togekiss' weaknesses too well
Electric:
+ Draws Ground Type attacks, which Togekiss is immune to
+ Not SR Weak
+ Resists Electric
+ Good STAB
- Thundnerpunch and Volt Tackle are not really good options for taking down Blissey and T-Tar, especially as the latter would require some Krillowatt-Draco Meteor Esquire thing to get it on the moveset
- Low damage, or recoil... nether is good. [I presume we intend to go physical, to handle Blissey and T-Tar]
Steel:
+ Resists Rock and Ice
+ Draws Ground-type attacks
+ STAB is actually decent for the intended goal. Super Effective on Tyranitar, and most users of STAB Ice/Rock type moves dislike Steel-type moves
+ Most Steels get Earthquake as a given, unless they float like Magneton, this will handle Electrics not named Zapdos.
+ Sr Resist, Toxic Spikes Immune, Persuit Resist
+ Physically-based type when it coes to moves.
+ Meteor Mash, should it get it, is good for dealing with Pink Blobs who try and stall you, even if this CAP dosen't get sweeper stats.
- Does nothing for the Electric weakness
- Quakeslide can handle both Togekiss and Steels.
- Bad STAB for doing much else in OU, like taking down Steels that Togekiss dislikes.
Ghost:
+ Draws Ghost-type attacks
- Doesn't do aything for Togekiss' weaknesses
- STAB is useless agaist Blissey, and almost as bad against Tyranitar
- Persuit Bait
- Gengar and Rotom-A use Thunderbolt
Water:
+ Draws Grass-type attacks, which Togekiss Resists
+ Resists Ice. Hits Rock-types Super Effectivly
+ Decent moves on both sides, Waterfall and Surf.
- Draws Electric-type attacks, unless we're re-making Swampert.
- Most moves are Specially-based
- Other bulky Waters tend to carry Ice Beam, so Togekiss can't switch in on those.
- Only draws a resistance, not an immunity, and it's not the world's most common or popular type.
Now, I might get burned at the stake for suggesting this, but here goes: I suggest the Steel type for Togekiss' partner. It covers the most weaknesses, can handle Tyranitar and Blissey, and draws the most common attack in the game to it, which Togekiss can switch in on. Bad STAB? Well, look at Metagross, he still Meteor Mashes away. My veiw on things is that this pokemon should be a supporter anyway, not a sweeper in it's own right, or Togekiss will become IT'S perfect partner, helping CAP11 to sweep, which is the reverse of the concept. So we should not make arguments based on 'Electric STAB > Psychic STAB'