First up, in case you're wondering about the wallpaper it's simply one of the new "live" wallpapers available in the iPhone 6s (if you use force touch it will move and it looks pretty cool). But straight up, if you're wondering if you should upgrade from the 6 to 6s I'd say - wait it out. Although the force touch and "live" photos are kind of cool, I don't actually use those features much at all. Now, onto the photo apps.
The #1 app for photo filters that I use is VSCO and it's been my go-to for years. To answer the burning question of "What filter do you use?" (from past to present) F2, C1, 04 and A6. I used to go for more of a haze on my photos with F2 but lately I've been appreciating a bit more contrast. I don't like to alter images to the point they look like they have artificial coloring, just enhance. C1 usually borders on the artificial side so I bring it down to at least an 8 (pictured below). You can always play with the intensity of a filter if it appears too dark or up the brightness.
I can get 99% of my photos edited to my desire in this app alone. I've tried others such as Afterlight and Priime (both of which my boyfriend uses, incase you're curious) but at this point I just know VSCO the best.
Quick tip: Always bump the sharpness. Sometimes a filter can cause the image to look a bit blurry so to insure a crisp image, sharpen! I do this especially with iPhone photos. It's not as important with photos from my Canon G7x.
I know that there's a Photoshop app but for little detail changes, I go to Snapseed. For those photos that have a lot of hard shadows or you want to add selected brightness, I love the "Selective" tool.
With "Selective" you can pinpoint edits. Pinch/zoom your fingers to determine the diameter of the area then add brightness, contrast or saturation. I also like that you can save the modified image to your photo album so that you don't have various edits of the same image in your feed (pictured below).
I also occasionally like the "Healing" tool for getting rid of a pesky pimple. If you're familiar with Photoshop it's like using the cloning tool. Unlike Facetune, it doesn't just blur an area, it clones another area of skin so it looks more natural.
While on the subject of FaceTune, I know that it's something that people can get carried away with. I know how easy it is to get caught up in altering the "imperfections" out of yourself but like my use of filters, I do my best to avoid altering anything to the point that it's not me. Sure my scars show a bit more in certain light or my face looks fuller at a different angle but rather than altering my face in post, I'd rather just take the picture in the right light. Does that make sense? I used to use the app to blur away imperfections but nowadays I use it on occasion to sharpen (or "detail") my eyes. I just figure people are going to see me IRL eventually and the real me can't be photoshopped.
If you're particular about symmetry, SKRWT might be your new BFF. Dylan actually introduced me to this app before Instagram built-in some of the tilt and perspective options but the downside to doing it within Insta is that it doesn't work on your full length images. Within SKRWT you simply have better and more editing options such as lens correction.
Finally, I have the GoPro and Camera Connect apps to connect remotely to my GoPro or Canon G7x. When I shoot vlogs in my car I use a GoPro mounted to my windshield. Thanks to the app, I can make sure the I'm in frame and stop/start recording by using the built-in wifi connection.
Camera Connect allows me to connect my Canon (wifi capable) cameras via my iPhone. This is how I send myself extra high quality photos for Instagram. You could also use it to remote shoot but I haven't used this capability yet.
So that's it! I think that's a pretty indepth look into what I use but if you have any other questions feel free to ask below.