My commuter has been a Schwinn I actually bought from a fellow ZSer here in Bartertown years ago, I converted it to single speed rather then keep up on maintenance. For the flat paved roads I usually traveled it has been a fine steed, but as one can expect gravel and any kind of hill were both its enemy. And it wasn't the greatest in snow and Ice either;
My objective was now to find a bike that:
1) was a decent commuter, somewhat splitting the difference between on road and off road performance, and performing better then my current bike in bad weather.
2) had the lowest burden of maintenance possible
3) had covering ground as its main job rather then speed or "trail" performance
4) was in an INCH sense possessing as much long term durability as practical
So I started hunting for my prefect BOBike. When jumping into a new hobby or wading into unfamiliar purchasing decisions my first goal was to constrain my choices to a reasonable number. As with most things, defining a budget was the first step. While I was initially hopeful $500 would be enough, after more research and searching I decided I would probably be looking at $1500 at the upper end.
Second decision was frame material. Aluminum, Steel, Carbon Fiber, and Titanium are the main choices, Carbon and Ti mostly priced themselves out as an option (although I tried for a long time to find a used Ti bike in budget, there are several makers semi locally so we have a lot of Ti on craiglist). Carbon also has fatigue characteristics that it would be easy to argue make a poor choice for goal number 4. While Aluminum is probably a very good choice for most folks, my inner luddite steered me toward a steel bike overall. The argument is that steel is more flexible and doesn't store fatigue like Al, which in the early days of mountain bikes was by all accounts a real problem but seams to have mostly been solved. The ride quality of steel supposedly has advantages as well but I didn't count on being able to tell the difference, and the largely fantastical argument that any welder in the 3rd world can ghetto fab your frame back together was also alluring.
The next big choice is tire and wheel size. 26" wheels have been the standard for ever, and in the Mad Max scavanging/trading/battlefield pickup for parts sense is very compelling. In a very superficial sense they look pretty stupid with a L/XL frame and a tall lanky guy on board. 27.5" is the new hotness, and by all accounts stands a good chance of being a new standard with performance off road bikes. 29" wheels have been around a bit longer and have more bike options then 27.5" at least for now, and have the best "rollover" and some would argue better traveling efficiency in general. For the commuter aspect I like the idea of being able to swap between 29er off road wheels and road bike wheels as an option, so from very early on I was working from the assumption that 29er was the incumbent choice and would need to be convinced otherwise.
Tire size is much less of a permanent decision, but must be factored into frame and fork clearance. "Plus" sized (mid-fat, B-fat, etc) tires are gaining popularity in bikepacking and gravel touring circles, being somewhere between 2.8" and 3.25" wide they split the difference between a normal trail tire and a fat bike. The argument is increased traction, flotation, and shock absorption at the cost of some speed and on-road performance, but much less so then a true fat bike. This loss of road performance didn't sound like my cup of tea, but I kept 29er+ bikes generally as an option, and tried to focus on frame sizes that would accommodate at least the small end of + sized tires, the theory being I could trade between a skinny commuter wheelset and a wider offroad/BO wheelset.
In general I was considering a suspension fork, but a full suspension bike was definitely off the table, and really a fully rigid bike was the incumbent. My thinking became that a suspension fork was generally in opposition to all 4 stated goals in varying degrees, and that I could always add one later if I changed my mind.
Due to past experiences I was pretty passionately opposed to derailleur as a rule, and was fairly sure that an internally geared hub (IGH) was the direction I would take.
So, a simple steel 29er with wide tire clearance? In bike circles this starts to sound very much like one brand, Surly. They more or less pioneered both the 29er and 29er+ category with the Karate Monkey and Krampus bikes respectively, they only make steel frames with understated aesthetics and while they are fairly cutting edge on tire size and clearance are more luddite on details such as axle widths, break options and general backward compatibility of parts. Once I knew what I was looking at I realized that many of the bikepacking, urban utility and 3rd world touring bikes that I had been using as a reference for the whole BObike project where in fact various breeds of Surly bikes.
Not being immune to groupthink and really itching for an excuse to constrain my choices I pretty much limited my search to Surly's offerings. The Karate Monkey was the first and is still the quintessential 29er simple trail bike, and is often adapted well to bikepacking and commuting. The price was right, with older used bikes going from $500 to $1000 generally, but many where setup as singlespeeds and break and gear options where more limited.
The Krampus was the first and similarly still the defining 29er plus bike, but while it can be pressed into service as a bikepacker or longer distance bike it is at its heart a trail bike, and the geometry and general design are geared toward "fun" and nimbleness more then load hauling and endurance. Similar to the Karate Monkey the bike has been around for awhile and it isn't hard to find cheaper used bikes.
The Troll and Ogre are probably some of the most obvious choices for turn-key BOBikes on the market, with the 26" troll being the objective, logical choice for true Mad Max or around the world touring, with the wheel and spare parts options being limited by very little. Likely 90% of thrift shops have at least one bike that could be cannibalized for parts for the troll, and garage sale options would be equally vast.
The Troll's big brother the Ogre gives up some of the wheel compatibility for the potentially higher performance of taller wheels. Both bikes sport some of the most mounting options on the market, with bottle bosses all over the frame and fork, you can put racks, fenders and bottle cages on at the same time, and often in the same spot. While most bikes can be adapted to these sorts of mounting options, having factory installed bosses make installation turn-key and more secure then most ghetto-fab options.
The final real contender on my short list was the ECR. For all intents and purposes the baby of an Ogre and a Krampus, it was made for plus sized tires but with the touring geometry and mounting options of the Ogre, it had been quite popular amongst bikepackers, and several prolific bloggers and forum posters had been advocating it as the perfect rig for long-distance bad road touring. Unlike the Krampus though, it has a pretty low bottom bracket, which meant that if I wanted to put smaller road-friendly wheels and tires on pedal strikes would become much more frequent.
In the end the Ogre won out. I decided I wasn't willing to take the mobility hit of a dedicated plus bike if despite my fantasies I was going to spend more time commuting then puttering around the backcountry, and as the compromise bike I figured it gave me the most options to experiment and at the very least clarify what I wanted in my next bike.
Although I see AR mags on that belt. I don't know where your loyalty really lies..... 
