Basic path to NC milling (for this new guy)?

Since my ancient vertical mill is breaking down more often than I
can tolerate, I may opt to trade it in. If so, I would like to
ensure I make the right choices to eventually do some NC automation.
Is there really any difference in the mill I choose (from a NC
standpoint?
Does the choice of DRO I buy matter? Does the DRO feed information
to the computer? If so, what is the connector, or interconnect type
I am looking for? Specific brands and models recommendations would
be welcome. If not, does a person have to add seperate location
detectors?
Motors: Enco offers a table motor they call "Servo". I am guessing
that is a brand name, not an actual servo motor. I will not buy any
table driving motors with the mill (I will not be able to afford it
all at once), but eventually I will add the motors, and would want
the motors to be addaptable to NC operation. I am familiar with
steppers after having built an NC plasma table, so I have a bit of a
headstart here.
Any info you can offer would help me. Again, if I buy a new mill, I
would want to have the right upgrade path to eventual home-brewed NC
operation. I checked the FAQ briefly. Thanks!