Motor Sizing for a Small Vertical Mill Spindle

I have an old vertical mill. It is fairly small, with about 12x8x12 inches
of travel in x, y, and z axis respectfully. That's really a guess, I don't
have the numbers, or mill, in front of me right now. The mill is not CNC,
but I would like to make it so over the next few months. It does not have a
motor to drive the spindle right now. I would like to use an AC motor, or
at least I think I do. I'm planning on using the mill mainly for plastics
and soft aluminum enclosures. That's not to say that I won't come up with
something else in the future that may be harder, but I'm just getting
started now. I'm not concerned with achieving very high RPM at the toolhead
right now, but I don't know if I will change my mind as I learn.

The Point:

Should I go with an AC or DC motor, and how big? I only have 120Vac
circuits available right now, though I'm considering running 230Vac to the
location of the mill (not for the sake of the mill, but just to increase the
service capacity of the garage the mill is in). How fast am I going to need
the spindle to turn? I assume that the spindle can turn slower if the feed
rate is low, but what's typical? Will I want to be able to set the spindle
RPM in software? In some machining publications I've seen, it looked like
some machines had a direct drive, that is with the spindle motor mounted
axially, above the chuck, without a belt drive, like a dremel with the motor
in the handle. The way this mill is set up, I think I could do that, or use
conventional drill-press style arrangement with a belt. Is one better than
the other?

My first guess is that an AC drive would be preferable over DC, because you
don't need a power supply. You just let the thing turn at whatever speed
and adjust the feed rate. I'm also guessing that a belt drive will be
preferable, because the belts give you some adjustment in the spindle RPM
vs. torque, but I like the look of having the motor mounted right there on
the spindle, and its how you look that's important. Of coarse, if you tell
me I need a 1HP motor, then it probably wouldn't look so cool, because it
will be too big. Choices, choices...

Thanks,

Mike