Sternguard = Kill-teams
Vanguard = Keepers
Terminators = 1st Company Veterans
(All of those are Lexicanum links for those who need more background on the DW)
So most importantly this gives you access to the Kill-teams of the DW in the form of the Sternguard.
watch-captain or a librarian. This gives you conveniently at least 1 Librarian for each squad of the 1st Co Task Force should you wish it, and provides you with a great great psychic bank.
Storm Wing- 1 Storm Raven Gunship, 2 Storm Talons. So while not hard Deathwatch per-se, this gives you some vehicles, and flyers at that, for your 1st Co Task Force if you want (that is outside of any dedicated transports you want to take in the task force, including Land Raiders...). To me, they also seem very very likely to be used by the Deathwatch for precision type strikes, etc. etc.
First Company Skyspear Assault Wing: 1 Stormraven, 1 Terminator Squad, 1 Terminator Assault Squad, 1 Venerable Dreadnought. Basically a combination of reasons for the the 1st Co Task Force and the Storm Wing support this one. AND it is what gives you access to DW dreadnoughts in this list.
Watch Captain, albiet a somewhat of a high cost. But these men are few and far between in the galaxy, and so would likely only deploy in force anyways. And once more, the formation is fully fluffy.
Strike Force Ultra: 1 Captain, 2 Terminator Units, 2 Terminator Assault Units, 1 Venerable Dreadnaught, 1 Stormraven Gunship, 1 Landraider Crusader or Redeemer. Actually my least favourite formation for this build (thus why it is last) it is made entirely of the same units as all the above, so I list it here for your convenience and completeness.
1- Imperial Fists- With all the Bolter Fire that the list brings to the game, particularly with alot of Sternguard, it is worth it for re-rolling the 1's.
2- White Scars- I would ONLY take this on the Librarians. I wouldn't even take bikes. I would just use it to give all my Death Watch squads Hit&Run. The only other okay one for the Librarians is Iron Hands IMO, and only if you really want to beef them up for survivability.
3- Raptors- A Forgeworld Chapter Tactic this one is pretty fluffy for DW IMO
-All units w/ out Bulky get Scout. Gain Stealth 1st Turn
-If you do not move in movement phase, treat all boltguns (including combi-weapon boltguns) and bolt pistols as a Heavy 1 w/ Rending.
4- Red Hunters- Another Forgeworld Chapter Tactic, this one really could show off their wide variety of skills, and gives you amazing psyker defence when combined with the Librarius Conclave, essentially allowing you to control that phase of the game.
-All units have the Adamantium Will Special Rule
-Once per game, you may declare x units, where x = the game turn, with the Chapter Tactics (Red Hunters) + Dreadnoughts may have one of the following rules until the beginning of the next turn
DEATHWATCH 2000 pt list (1997 pts)
Formation: Librarius Conclave: 5 Librarians (670pts)
Librarian (WARLORD): 210- Mastery Level 2, The Armour Indominatus, The Shield Eternal, Force Axe, Auspex, Teleport Homer
Librarian: 110- Mastery Level 2, The Primarch's Wrath, Force Stave
Librarian: 95- Mastery Level 2, Bolt Pistol, Force Sword, Teleport Homer
Librarian: 125- Mastery Level 2, Terminator Armour, Force Sword, Storm Shield
Librarian: 130- Mastery Level 2, Terminator Armour, Force Axe, Storm Shield, Auspex
First Company Task Force (1327)
Sternguard (9) Death Watch Kill Team: 293- Vet Sarge w/ Power Sword and Combi-grav; 2 x Veterans w/ Combi-flamers, 1 x Veteran w/ Heavy Bolter, 1 x Veteran w/ Flamer, Drop Pod
Sternguard (9) Death Watch Kill Team: 348- Vet Sarge w/ Power Sword and Combi-grav; 2 x Veterans w/ Combi-melta, 2 x Veteran w/ Grav-cannons+Grav-amps, Drop Pod
Vanguard (9) Death Watch Keepers: 261- 8 x Bolt Pistols, 3 x Power Swords, 2 x Power Axe, 2 x Power Lance, 1 x Power Mace; Vet Sarge w/ Bolt Pistol & Power Fist; Drop Pod
Terminator Assault Squad (5) Death Watch Veterans: 225- 5 x TH&SS
Terminator Squad (5) Death Watch Veterans: 200- Sarge w/ Power Sword and Storm Bolter, 1 x Chainfist, 1 x Assault Cannon
So the Warlord goes with the Keepers, the other 2 power armour librarians in the Kill Teams, the one with the Teleport Homer goes in with the Gravcannon Squad (or that is how I would do it). The Terminator Lib with the Auspex goes into the stormbolter terminator squad.
So the first kill team is equipped in a super fluff sort of way. One of the only fluffier things you could do is take dual lightning claws on the sarge. HOWEVER both kill team sarges have a combi-weapon and power weapon rather than a pistol. This is a nod to their old fluff and True-grit rule where they could treat a bolter like a pistol in combat, and wielded both. BUT The first squad is decent at eliminating infantry blobs.
The second kill team is just to be a good monster/armour hunting squad.
The Keepers are so cool in the fluff I couldn't go without them. A great way to get some AMAZING conversions into the army.
The Terminator Squads are self explanatory IMO. Sure standard terminators aren't that great, but they are super fluffy and I would personally use these guys.
So there you have it. Codex Adeptus Astartes: Deathwatch.