Armor: Rosenkov Chest/Legs; Armax Shoulders; Kuwashii and/or Recon Head
I use this setup because it's functional and it provides me with bonuses I want. Plus... it loots rad... which is actually the only real reason I wear it lol.
Weapons:
Sniper Rifle: Viper - improved barrel, scope
Shotgun: Crusader - armor piercing, heavy barrel
SMG: Tempest - weight reduction, extended clip
I like being more mobile and being able to pop shots off whenever I want, and the Viper is really the only Sniper Rifle that lets me do this to the degree that I want it to. I don't really go for the heavier rifles. I switch out between Ice and Disruptor ammo on this. This is my primary weapon, and I pretty much kill 90% of the mission enemies with it. I don't use the time compensator mod. I don't really need it, plus it's just kind of annoying with a semi-auto gun. I did use the Indra for a while, and I liked it a lot. But this one suits my style a little better.
The Crusader was a late addition because I really needed a heavy hitting weapon for armor piercing, but I didn't want to have to sacrifice my position. The heavier options to way more damage, but they also blow my weight threshold. This really was the only solution, unless I wanted to get the Graal... which I tried... and hated. This Crusader is pretty badass, though. It has superior range equal to that of a Sniper Rifle, zero spread for long range, so all your damage is focused into one singular spot, really great damage for its speed with the heavy barrel mod, and pin-point accuracy - it shoots and hits exactly where you point it no matter what. It's basically a high powered, semi-automatic sniper rifle with a quick reload and fire rate, but doesn't have a scope. It's perfect for armor piercing.
The Tempest because... it weighs nothing and is the best option in this category if you get rushed. The Geth SMG is better in stats, but I don't like the charge-up time, plus its still kind of heavy even with reduced weight. Put Disruptor on this, and you've got a holdout weapon against husks, or generally anything that typically likes to get close to you or has shields or barriers.