I enjoy my Widow ranged and this is a guide to exactly that, a ranged Black Widow who can keep her distance while bringing the pain. She uses both physical and energy so we'll be gearing for ranged damage, which will help both since all but her passives and her sig are tagged ranged.
This is NOT her highest-damage build, as her hybrid melee/ranged beats it in DPS. But this build can help keep you alive longer, as it gives you a bit more distance from your enemies and keeps you mobile while still doing very good DPS. So if you're looking for a hero that plays like a ranged rogue, able to get in some sizable hits and pick enemies apart while avoiding their damage, Black Widow is the girl for you.
UPDATE
I've updated the build because her spirit sustain is doing better now and the new Civil War drops are helping her out a ton. I swapped in the new Heavily Modified Mercenary Assault Rifle for her slot 1, since the huge amount of ranged power ranks on it allow us to hit 50 on all of our skills now, which we couldn't do before. I also swapped the new Crossbones Teaching Credentials (Physical) artifact in and those two changes help up her DPS a bit from where it was before.
The Build
Here's the build on the info site:
Main DPS Rotation:
Coup, Drones, Sig, Coup, Drones, Grenades, Kiss, Barrage until the damage layers (Coup, Drones, Grenades, and Kiss) are back off cooldown. With the new changes, her rotation is a smooth 8 seconds all around, except for when her sig is up and we can take advantage of some burst with her non-dot layers.
You'll start seeing bigger Coup hits after the mob is under 50% because of the executesque mechanic on it. And we lead with Coup because of the huge damage buff to ranged powers it gives. (Over 800 DR at rank 50.)
Utility and Extra Skills:
Vulnerability: I just one-pointed Anti-Personnel Grenades for use when soloing, as during raids and group content, someone else is likely to already have used vuln on mobs and the skill itself is a DPS loss in a rotation even maxed.
Stealth, Attack Speed: Silent Killer is what we use to drop aggro, which is important since Widow can't take much damage. (Sure, she's an Avenger and regularly faces cosmic-level threats, but I think Gaz is worried about her nails breaking or something, which must be why she's so ridiculously squishy.)
Someone suggested using power duration gear to extend both buffs, but with her new gear and her huge dependence on her 4 usable uniques for skill ranks, there's not an elegant way to get that without giving up DPS, which she's already low on. With my current gear, I get 8 seconds of uptime on both, which actually works out pretty perfect, as you can weave them in with your ranged damage rotation. You most likely won't need either buff for trash, and you'll most likely only need the mitigation on AoE bosses (especially since she now gets 10% mitigation all the time), which is why I didn't add these two utility skills or the vuln into the main rotation above. Use as needed.
Team-Up 2.0:
Natasha's getting some real help with the Team-Up 2.0 revamp! @Tobbie did a great job breaking down DPS coming from the various Teamups in this thread: http://forums.marvelheroes.com/discussion/205152/team-up-2-0-ttk-tests/p1 And he came up with the same conclusion I did - Clea rocks. She's dropping THREE party boosts (Constitution, Power, and Toughness), none of which Widow gets natively in her kit. That's a good bit of extra HP, healing, and defense from Constitution and Toughness, and a nice boost in DPS from Power. Plus Clea is ranged too, so she stays back and drops dots and single-target damage at a decent clip to add to our DPS. She's the winner in the Team-Up race so far!