1. A good tent - I know this one sounds like an obviously one and it is, but guys, the world of tents is huge and complex. Like any big ticket gear item, it's good to do your research on it. On the trips I'd been on before, any old tent with a tarp strung above it would do. In Scandinavia, there are often no trees around to tie tarps to (too high elevation for trees to grow), and it would be useless against the wind storms that often pick up at night. Our tent is a special kind of tunnel tent that stands up super well to wind and rain, and has a huge vestibule in the front to keep all your gear dry. I can't say how many times how nice it is to have a vestibule to eat dinner in if it's rainy, or to have space to put your muddy boots so that they aren't next to your face. This tent stays amazingly dry, like zero condensation in the mornings. I hate nothing more than a drippy tent, ugh.
2. A down vest - I tend to get really cold on camping trips up here, especially once the sun goes down and the temperature drops, and then I get really grumpy. For this trip, I invested in wool long underwear (so good) and a lightweight down vest to layer over my fleece or under my rain jacket if I was super cold. The vest kept me so warm and cozy, it was like wearing a mini sleeping bag. They aren't the most fashionable in the world, and I resisted spending the money on one, but I quickly fell in love with the functionality.
3. A silk sleeping bag liner - I know this sounds like a fancy item that you don't really need, but you do. Of course, a good sleeping bag is a good idea (preferably down, and rated for lower temperatures - Mark has one like this and I have the slightly cheaper and bulkier version), but a silk liner helps keep you much warmer. Plus, it's easy to wash once you get home and you can always use it on it's own for warmer trips or hostels. And they pack up into a tiny bundle.
4. iPhone + Kindle App - Again this might seem like a luxury item, and I know there are people against taking technology on hiking/camping trips, but it's so worth it. We used our phones for GPS navigation (so helpful, and nice knowing that we wouldn't ever be totally lost), for taking photos and videos when it was too stormy to take out our big cameras, and although this last time I brought my Kindle, next time I'll definitely just use the app for reading. We've found that without having a campfire to tell stories around at night, reading something in our tent is the next best thing.
5. A opaque water bottle + headlamp - I saw this little trick on Pinterest: a headlamp wrapped around a bottle gives a nice lantern effect. When you are hiking, you can't exactly bring actual lanterns with you and it gets pretty dark out in the wild, so it's really nice to have a bit of atmospheric light to read your bedtime stories by. Plus, these wide mouth Nalgenes are the best to gather water from streams with. It's nice to be able to see the water, and they are super lightweight.
6. Hot chocolate - Camping isn't camping to me if there isn't something with chocolate and marshmallows. Although you can't make s'mores, a good hot chocolate is also a very good thing when it's cold. We've just bought Nestle packs before, but next time I'm going to try making my own with this mix which we use at home, some powdered soy milk and mini marshmallows. Since hiking food is generally not super great, I've found that adding little luxury items makes a big difference: dried blueberries and mango in our morning oatmeal, nice gluten free crackers and vegetarian pate for lunch, etc. We always bring freeze dried hiking dinners with us, since they are by far the easiest, and so far this brand has been the winner.