This isn't exactly along the lines of most of the bikes here, but here goes.
I worked in a couple Schwinn shops for about ten years, starting in high school. I had a few nice bikes right up until I started buying cars. I kept the last mountain bike I bought, and rebuilt it a year or two ago. It's seen a few incarnations through it's life but now it's back to a trail riding configuration. A 1988(?) Rockhopper Comp
My latest bike is a long story. For years I had been wanting something with an internally geared hub. I also wanted something old style, so I was going to buy a Schwinn Typhoon frame and build it up. Then I realized I could find a new bike with the same style frame and get the entire bike for a lot less than building something.
Amazon had one on sale, a 7 speed with a derailluer so it was already set up for hand brakes and shift cables etc. And it was just under $200. I figured what the heck. If it was trash I'd keep the frame and throw everything else away.
The bike showed up.
As expected, it wasn't going to be a case of just bolting it together. For instance, none of the bearings were greased very well.
I rebuilt the entire thing and was pleasantly surprised with the result. With everything on it rebuilt, it wasn't a bad bike. But if the average Joe bought it, bolted it together, and tried to ride it, it would have sucked. Which is what the Amazon reviews showd too.
So yeah, I rode it mostly stock for a season (aka maybe three times)... but I couldn't get the brakes to stop squealing. So I ordered some new pads. Plus some non-painted rims. And spokes. And hubs, Deore XT front and a 5 speed Sturmey Archer with a drum brake for the rear. And as long as I was doing that... well, you get the idea.
So now it looks more or less like this. I've upgraded a few other things since these pics
Yeah yeah yeah, the thing is a tank but I swear it rides so much better than it has any right to.
EDIT: It still has a rear derailleur because for some annoying reason they used vertical dropouts. A regular tensioner doesn't have the reach it needed. But I did at least upgrade from the plastic POS shown in the pics.