Cell phone with waypoint app (I use AlpineQuest for Android). Most hiking trails are maintained by volunteers, and I'm one myself. Hikers are the best source for reporting trail issues. A waypoint app allows anyone to record the gps coordinates (and usually attach a photo) of trail problems and email it to your local trail maintenance organization so they can know exactly where the problem is. Also functions as a book at night.

I always bring some extra spices and hot sauce...Trail food is often bland and boring, so I like to be able to add and switch flavors.

An extra thick sleeping pad for a good night's rest.

An AeroPress coffee maker adds a little weight to my pack, but the excellent cup of coffee it offers me in starting off the morning makes the small amount of extra weight well worth the carry.

I bring full headphones rather than earbuds because I enjoy relaxing to music on the trail and in camp.  Since I'm wearing them most of the time they don't feel like extra weight.  

Empty gatorade bottle for those c-o-l-d nights...

My one go-to luxe item is a pillow. Mine is a small, inflatable model with a microfiber cover. It gets a little wobbly if I toss too much. But, it's small, light and provides just what I need to wake up rested.

This may sound silly, but my favorite "nice to have" item that finds its way into my pack ALWAYS, is a small candle lantern in a metal and glass sleeve that I light at dusk and hang near my hammock. I typically leave it lit until it burns itself out 8-9 hours later. Many of my peeps think I am a dork for carrying such a frivolous item however, my little candle enhances the camp ambience tenfold! When I wake up at 2 a.m. to experience nature in the dark, my little nightlight says "welcome back, we were expecting you!"

I carry a Sony AM/FM radio, a very small one that only weights a couple ounces.  I listen to music or other entertainment right after snuggling inside my sleeping bag for the night.   Whether I am at Tanner Rapids in the Grand Canyon or anywhere in Death Valley or even far back in the Wind River range in Wyoming, I always find something to listen to as I relax and drift off to sleep.

My Cell Phone.  I use it to take notes and pictures, I play solitaire on it, and my Kindle doubles as a book.

I would have to say that I have 2 'luxury' items that I can never quite bring myself to leave at home when heading out on a trip;  my 21" bucksaw, which just makes processing dead wood for fires immeasurably more pleasant, and a collapsible vinyl sink, which makes washing anything from dishes to hair to clothing so convenient and while certainly neither is necessary, they are to me worth the extra weight.  A lightweight chair would certainly go a long way to completing that trifecta of luxury items to make 'roughing it' just a bit less rough, and all the more enjoyable.

My beloved Sea to Summit Aeros Premium pillow is my luxury item.  I sleep so much better with it.  I tried the clothes in the stuff sack pillow, and it was an epic fail for me!

Two luxuries I'll always bring along are a small container of hot sauce (Franks or sriracha) to zing up the dehydrated food, and a small flask of scotch for fireside sipping. My father-in-law was fond of the saying "any fool can be uncomfortable in the bush", so I take him to heart and balance titanium with these items that contribute to enjoyment. 

Coffee grounds and an AeroPress

A inflatable pillow may be a luxury to UL hikers but a good night's sleep is wonderful.  A chair may be my new luxury item soon!

Coffee Peculator, it works great on the camp fire.

A pillow

My luxury item is an inflatable pillow inside of my stuff/down pillow.

I've recently purchased the BA wide long Q. Core sleeping pad. It is my luxury item. I've tried everything from the thin gray foam pads to lightweight pads. I never really had a good nights sleep with any of these type pads. Everything else I reduced weight on so for me sleeping on a pad like this is sheer heaven. 

A great camping pad, such as my Big Bertha.  If I don't get a good nights sleep, I turn into a grumpy wild animal!

My lux item is a 13000mAh external battery pack. I never want to be without tunes.

My luxury item is a camera and compact full tripod.  The tripod weighs a pound but it lets me share the beautiful intricate macro details of what we see on the trail with other people who can't or don't get outdoors the way we do.  I like to think this might pay dividends in the future for preserving and protecting our wild places because every heart that values the outdoors that we are so disconnected from in modern every day living has the potential to make a decision in their job or the voter booth someday.  Thanks for offering such a great item for a giveaway!  These chairs are really nice and I'd love to add that to my pack.

My backpacking luxury item are the instant coffee packets that I wouldn't leave home without (like Via, but I've used others).  I'm not addicted to the coffee, but I find the smell of damp leaves and fresh coffee an intoxicating mix. 

Luxury items for me is coffee of any sort.  While still laying in my warbonnet hammock pure heaven on earth