I like to pack small, tight and light. And I'm cheap, too. Everything for a trip has to fit in my Jesse Bags and in the top box - no outside baggage.
What has worked best for me for the past 4-5 years is the following: Big Agnes Insulated Air Core Large, Eureka Silver City (30 deg F) and a Polarfleece lightweight sleeping bag/liner. I've slept into the 20's in pure comfort AFTER I started wearing a balaclava on my bald head on cold nights or a hat on less cold nights.
The greatest purchase that I have ever made was the Big Agnes Air Core pad. (lists about $100-$120) Don't over inflate and you will have more comfort. This provides more comfort and warmth than anything else I've found. It packs reasonably small but I do need to carry a compressor to fill it up on every set up. No big deal. Insulated side up for cold weather, plain side up for hot nights.
The Silver City ($65 when I purchased mine) was decided upon after lots and lots of research. Synthetic is best for my motorcycle riding/camping. For the price, I doubt the features of this bag could be beat. This bag compacts exceptionally well and stays warm even after long term compacted storage. Comes with its own stuff sack. It's good into the 30's without the liner. Anything much less than 40's and I will add the liner bag. I'm satisfied with Eureka's line of products. They also make some great tents as I use a Mountain Pass 3XTE.
I use a cheap Polarfleece liner bag ($12 on sale) for my cold weather liner. Anything less than 40 degrees and I use it as a liner although, on a recent trip to Oklahoma, I spent a night in the mid 40's with just the Polarfleece bag and I was comfortable until later morning (and then I just pulled my MC jacket over me for added warmth). When this bag is added as a liner to the Silver City, I'm very comfortable into the 20's and maybe colder. I have yet to test anything colder than mid 20's.
Most importantly for cold nights - add a hat on cool nights or a balaclava for cold nights. This is most important if you are follically challenged as my head is. This is also where a mummy style bag with a draw cord will make a huge difference in comfort.
Pillows - I've got a Thermarest dogbone shaped inflatable. ($35-$40) Save your money as this one sucks! I also have a cheap Cabelas that was on close-out for $1.50 which works better than the bone. I've recently purchased a memory foam pillow from Bart here on the forum. After I split that in half to decrease my head elevation, I found pillow nirvana and the best 4 nights of camping sleep I've ever had! And, this pillow stuffs into the Silver City's pillow pocket.
Don't I wish I had that during our summer trip where we camped 13 out of the 15 days on the trip.
I would say that the most important selections in the importance of order (for me, anyway) are: Sleeping Pad, pillow, bag, liner bag. Remember, you get what you pay for. Buy cheap, get junk in most cases. My cheap air mattress lasted a couple of months but my girlfriend has used her BA pad for 1.5 years of continuous use in her apartment on a nightly basis without any problems.
And Patrick, one of these days we need to schedule a ride on the MS river levee roads.