I am currently using a 175mm FSA Gossamer crankset with a 46/34 setup. It was in the parts bin when I built my bike so it is fine for now but has a huge amount of deflection and could be quite a bit lighter.
My price range is flexible. I will be buying this used or through QBP but mostly I'm looking for what will be at least 100g lighter than my current crankset which is almost 900g.

Also, my frame is english threaded, not BB30.

What is everyone running and what would you suggest as an upgrade?

Thanks.

Probably Dura Ace 7900 is the best compromise in terms of weight and stiffness

Why not go with a force crank? QBP has them cheap, and they can take one hell of a beating. Also the chainrings are less expensive to replace compared to a 7900.

FSA SL-K. Its strong and light.... surprisingly good considering it comes from FSA.

Campy UT standard with a 39T single ring or 46/39 double setup.

DA7800 crankset with 46T DA ring and a 38T inner.

This is assuming the bike is used primarily for racing. If you are doing more general adventure type riding, I'd think about a 46/36 setup.

My cross bike is my go-to bike for all seasons. Right now, it is my only steed that is built up. I've considered using a 42 in the front but am leaning towards 46/36 or 46/38 right now.

Current CX setups...
Ridley X-Night: DuraAce 7800 Cranks/ Chris King Ceramic Road BB/ 46-40T Chainrings
Ridley X-Fire: SRAM Red Cranks/ Mega Exo BB/ 44-38T Chainrings

This season I used a SRAM Red compact crankset with FSA 46/36 chainrings. This combination has worked well for me.

Has anyone used these or any other cranksets in a 1x10 configuration? I'm surprised to see that so many people aren't using a single ring in front. What's the reasoning behind this?

I run Campy UT carbon cranks, Specialized S-works cranks, and DA7800 cranks all with single rings. I've never needed more gear than a 39x11 in a CX race. On my gravel road cx bike I've got a double with a 46t outer rim.

I went with a 42T single front ring paried to a 12-30 9 speed Shimano set up on DA 7800 cranks. I loved it but given the speed of the races I do, and how competitive the guys are, I was getting left behind so changed the single to a 44/39 which is much better. I would be left for dead on dry grassy sections in my 42-12 - too small and no sprinting ability. I'm a bigger guy and can take the gear inches but mainly, I had no choice if I didn't want to spend my races getting passed.

I got a black TA 44 ring which looks great on the 7800 cranks. They are still pretty and given that anyone who uses a SRM still rides them, how bad can they be?

I also used the single ring for a while, but I realized in many situations the chain line was not optimal and it's a wasting of power

I could see running out of a 42/12 for some but I like to spin at a high cadence and my legs aren't what they probably should be. Thanks for the critiques on both sides of this.

What is the realized weight savings of 1x vs 2x? Does the ring guard and inner guard keep things breaking even or can I expect to shave a few grams?

I'm calling b.s. on a non-pro running out of gear with a 42x12 setup during a CX race.

42x12 at 120prm is 34mph with a 700x35mm tire. 44x12 gets you 35.5mph.

42x11, as a lot of people would use with a 11-28 cassette gives you 37mph in a sprint.

A 39x11 results in 34.4mph at that rpm.

Having one less thing to think about during a race is a much better advantage for me, than having a big ring. Heck, one of my bikes has a 46/39 and I just leave it in the 39 for cx races (since my other race bikes have 39T single rings.

Now, a 44/39 setup might be decent. If it's fairly flat, put it in the 44 and leave it there. Some hills? put it in the 39 at the start and call it good. But even then, there is a LOT of gear overlap.

I used a 44/38 this season, and I only used the 44 for flatter, grassier courses. I liked the set up because I still had two options but less chain length (i.e., less chain slap). I used a 12-27 cassette.