So, the DM of one of the games I am in just posted this on another forum and I thought it would be worthwhile to repost here, both as an indication of where my GMing style is evolving and also to let those of you not familiar with the OSR style of play what to expect, 'cause I think he pretty much nailed it.
Right now, for me, D&D means (in no particular order):
A. Random Encounters.
B. At least some Random Treasure
C. Reaction Rolls
F. Magic Items cannot be purchased under normal circumstances.
G. Magic Users need to find or trade for most of their spells (you can't just go out and buy scrolls ala 3.x)
H. Overland travel uses hexmaps and can get you into random trouble. Placing lairs and mini-dungeons in a lot of hexes is a great idea.
I. Plot. Hooks. Everywhere.
J. The PCs are (comparatively) badasses, even after a fairly small number of levels. A level 9 dude is a Lord by strength of arms. A party of PCs that are even level 3-5, along with some retainers and warhorses, are enough to be really heavy hitters in most contexts.
Keep in mind that he is currently running a game using ACKS, where the levels max out at 14. In BECMI (and Dark Dungeons), the max mortal level is 36, so there is a little bit of expansion in terms of power.