sounds like a great vacation!well both areas are nice and been awhile since i was at BC so vertical may have more upto date info but when I was "shopping" for an area to buy in I prefered steamboat over all the I-70 areas. BC would rank highly, but is more expensive and high end, steamboat has less of the vail flavor, still, although changing fast, a real town with real flavor. all those resorts will be crowded over president's day,but at steamboat after getting up the gondola (and there are ways around that as well) you can avoid major lines by a) skiing storm peak, b) taking lunch after 1-1:30, c) skiing the singles line, d) avoiding sundown express (lift) or Heavenly Daze (run). You don't really need a car there, great views, decent shopping (but not on the level you'd find near BC probably), good food.
I always lobby for steamboat unless the conditions suck and I think they are quite nice at the moment. Has a whole different feel than those on the I-70 corridor, although you do get a great deal skiing loveland, a basin, keystone, copper, and so on (but boy do you get the people as well)
either way, nice areas and you'll have a grand time no matter where you go!