#1 What travels would consider ideal.? . . . In X, Y & Z
X Probably a couple of feet. It's not that critical for me, as most of my parts are round, and those that aren't round aren't that big, but I wouldn't limit the X when it's relatively easy to make it longer.
Y Ideally minimum 250mm, possibly 300mm. This is where most small mills fail for me.
Z I'd want enough height so I can fit a decent (probably 8" or 12") 4th axis under it, so enough to probably get a good 400mm under the spindle nose, and still touch the table with a shortish tool
#2 What's more important to you Bed size or Travel.? (Consider often you'll see 3ft+ tables with one or two 6" vices taking up only 18" space.)
Neither really. As long as the bed has a bit room either end of travel, you work with what you've got.
#3 What would prefer to use Vice or Fixture plate.?
Both, although if I had the Z room, I'd probably get a Pierson pallet system, then mount what I need on pallets.
#4 What material cutting ability is most important Steel or Aluminium.?
Both for me. I need to hog lumps of steel down for repairing things, but most production bits are aluminium.
#5 What's an ideal footprint.
As compact as you can get the above with an enclosure, but still be able to overhang the table a bit when needed, or removable panels for the inevitable big bits (I do like the idea of the fixed table/sliding head setup used by Chiron, but it does complicate things)
#6 Bench mounted or Freestanding..?
Either as long it has a decent enclosure, and coolant tank.
#7 Fully Enclosed or Open.?
Enclosed. I've been soaked by coolant enough times to know enclosed is the only way.