Personally, the ballasting circuits that I prefer for fluorescent and HID lighting are lag type autotransformers (HX autotransformers) and reactors (chokes) because these types of ballasts can run a wider variety of discharge lamps compared to lead type ballasts such as CWA autotransformers and they can run lamps more smoothly than lead type ballasts due to the sine waveform seen with lag type autotransformer ballasts and reactor/choke ballasts while lead type ballasts have a more distorted waveform.

Does anybody else have a preference for a particular ballasting circuit like me?

I prefer reactor type ballasts.  Simpler and more reliable, takes up less space in fixture.

In general, magnetic over electronic every time, unless the lamp is specifically designed for an electronic ballast, such as the Philips CosmoWhite series. But whatever type of ballast, for me it has to be the correct one for the lamp, as determined by the lamp designers and manufacturers.

Think about it; they spent possibly many years and a lot of money developing lamps and the ballasts to run them, why use anything else..? One of my primary interests is how ballasts and discharge lamps work, I have amassed a large collection of documentation from places like Lamptech and other sites such as the lamp manufacturer's spec sheets, I don't need to physically experiment with lamp/ballast combinations because I already know what works, the designers and developers have done the work for me.

What, no carbon arc lamps? 

loljustkidding

I tend to prefer the ballasts that provide the appropriate voltage and current to a lamp.

("You don't say!") 

That is, unless the lamp is spent. From there, the more power, the better! And then, mister MOT often gets involved LOL.

With carbon arc lamps, there isn't anybody out there with a magical answer, I've gotta figure everything out by myself. But since virtually all carbon arc lamps' documentation's copyrights, and even their patents, are now expired, I've got plenty of texts to read on that matter!

--------------fluorescent--------------
It all depends on what the light is going to be used for...

> If its going to get allot of use (for example a plant or aquarium light, where it'll be running 8-10 hours/day everyday), then electronic (ideally programmed or rapid start). reasons being its more efficient, and produces less heat.

> If its going to just get occasional (or frequent minimal-time) use, either electronic(any start method) or magnetic is fine (rapid-start or preheat).

> In most cases I will want to use the correct ballast for the lamps, but I'm also ok with doing a 'overdrive' setup

--------------HID--------------
Since HID is a heavy power user, it is not something I would be running hours. Magnetic ballast is perfectly fine by me (ideally a HPF one)

In all* cases I would use the correct ballast.

* = except something like SOX where the correct ballast may be very hard to come by, where I might try a WorkHorse electronic ballast

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Note:
"Weird tests" done out on the patio I'm totally fine with trying a totally wrong ballast to run a fluorescent (or 'something close' for a low-power HID).
But these are something that would not be trusted running long-term, or unattended...they are as the name implies "tests/experiments"...they would also be done with equipment that is 'nothing special' & not a big deal if I end up frying it .LOL.