cooljolteon here, with my set of movesets, consisting of: Physical; Special; Mixed; and Support; followed by other options.
Physical Sweeper
Delibird @ Zoom Lens
Hustle
Adamant Nature [+Atk; -SpAtk]
252Atk/252Spd/4HP
-Ice Punch
-Aerial Ace
-Brick Break/Focus Punch
-Return/Substitute
Ice Punch and Aerial Ace for STAB, with AA specializing in completely ignoring Hustle's accuracy fact. Use Brick Break and Return, or Focus Punch and Substitute (yayz, Sub-Punch!). Zoom Lens fixes accuracy problems, and Delibird doesn't need to worry about going last - it will normally, anyway.
Special Sweeper
Delibird @ Icy Rock/Wet Rock
Vital Spirit
Modest Nature [+SpAtk; -Atk]
252SpAtk/252Spd/4HP
-Hail/Rain Dance
-Blizzard/Ice Beam
-Water Pulse/Signal Beam
-Hidden Power (Ground)/Swift
Use Hail if you're using Blizzard, and Rain Dance if you're using Water Pulse with Ice Beam. Hidden Power Ground takes care of pretty much all of Delibird's weaknesses, but if you don't want to get too technical, use Swift. Signal Beam is another 4th Gen option. (BTW, that's why I didn't go with Insomnia - you're going to have a 4th Gen move on this one, anyway) Icy Rock lengthens Hail, while Wet Rock lengthens Rain Dance.
Mixed Sweeper
Delibird @ Life Orb
Vital Spirit
Hasty [+Spd; -Def] or Naive [+Spd; -SpDef]
252Atk/252SpAtk/4Spd
-Ice Beam
-Return/Swift
-Brick Break
-Aerial Ace
IB and AA are for STAB. BB is for coverage, and R/S is for...lack of diversity. Life Orb increases the damage that Delibird will do.
Support
Delibird @ Icy Rock
Vital Spirit
Timid Nature [+Spd; -Atk]
252HP/252Spd/4SpAtk
-Hail
-Blizzard
-Toxic
-Substitute
Hail combined with Toxic will take opponent's out fairly quickly, with Icy Rock lengthening Hail. Blizzard is for the prevention of being Taunt bait. Substitute (basically) prevents Delibird from taking damage.
My fave Pokemon:
Jolteon
Celebi
Pichu
Serperior
Umbreon
Nidoking
Nidoqueen