FlyLite

I use Western Mountaneering FlyLite 36F bag which is 15.7oz. You’ll be fine in 40F, but with clothes on.

If you are brand new, get something cheap and on sale. Fair chance that you either will give up backpacking after a few trips or realize that you want to invest more in high-end gear.  You eventually need a quiver if tents, sleeping bags, and packs as no single one is great for all conditions.  For summer, I mainly use: flycreek 2p tent, Western Mountaineering 20 or 40F sleeping bags, and a daypack with side straps that cost about $60 and weighs roughly half a pound. 

WM continuous baffle design kinda is a hybrid. You can shift the down from top to bottom and reverse if its too hot/cold. So you are basically resting on the 2 thin nylon layers. If this is too warm, zip it up and use it as a blanket. No drafts, no straps,… you can take a model without a draft collar to safe weight and wear your puffy inside. Highly recommended!

Western Mountaineering mummy bag. I do a lot in shoulder season and these are very warm for the weight

I liked my quilt when I was doing shorter trips. Once I started doing months at a time I grabbed a western mountaineering bag and I have no regrets. Helps me extend a bit more into shoulder season

Western Mountaineering, Feathered Friends or Marmot for bags. Enlightened Equipment, Hammock Gear or Katabatic for backpacking quilts. Not cheap but quality and comfortable.

I've been a quilt user for years, but if I were looking for sleeping bags, I would go with either Western Mountaineering or Feathered Friends. You absolutely get what you pay for with either brand. Awesome quality.

There isn’t really an absolute best, but I like Katabatic for a quilt and western mountaineering or feathered friends for a bag. I prefer quilts down to around the low 20s, bags below that. Having a pocket in your quilt for a sleeping pad seems silly to me.

Good pad. Stick with that. Edit: (I forgot about the Nemo eclipse. That's something to look at. I don't think they're ready to ship yet. I don't know that factually. I think they're officially going on sale in march. REI was doing pre-orders.) Someone mentioned Western Mountaineering. That's the best. But they're expensive. I don't know if I'd recommend it for a beginner. I have one and it's totally worth it. If you know you're going to be out there, then maybe eventually you want to make that investment. In general about sleeping bags look at the EN or ISO Comfort rating. If they don't have that, you probably don't want it. That's an incorrect statement. Because even some top brands don't necessarily publish that for certain bags. In which case you just really need to look deeper into that bag. To give you a specific example, Western Mountaineering has EN number is published on a chart under their faqs. But that only goes down to their bags that are about zero rated and above. That doesn't mean that they're cold weather bags are crap. The exact opposite actually. But a lot of budget brands are throwing a temperature rating on there that may be more related to the extreme limit number which is survivability and you'll just be cold. If you want to look at the difference between the comfort, limit, and extreme limit rating, you can. But just stick with comfort. Maybe build in an extra 10° from what you actually expect to sleep in. That's a heavy tent. You can save a lot of weight there. Let me offer a specific alternative. Durston Xmid 2. It's a trekking pole tent. If you wanted to try trekking poles, this is a great way to save weight. If you don't want to use trekking poles, Durston sells ZFlicks poles. You'll still be significantly lighter than the Half dome 2. R/durstongearheads Naturehike is a budget brand with tents you can look at to see if one would work for you. You'd save money. And probably can come out a fair amount lighter. Check out r/ultralight. I'm not saying you should go full ultralight. But if you're going to be backpacking, save weight where you can.