Well, the Angle is protected by two rivers. That's a pretty effective natural barrier in most situations. Also, it was fertile land and far removed from the major center of traffic in Eriador (Bree) where spies would be most likely to visit. And yet the Angle also provided access to Bree (by road) and Tharbad (by river). Then the proximity of Rivendell assured it would not be far for Aranarth to travel to see his son (and so on down the line of the Heirs of Isildur). And since the Bruinen served as some sort of barrier on the east, the most likely direction of attack would be from the north. If the Dunedain lived near the tip of the Angle they would have plenty of advance warning.

: On a final note, I also believe that the note concerning the
: Angle was made under the impression of a romantic notion that
: the Rangers should really live in the wilds, and the lands east
: of Mitheithel were the wildest in Eriador- without considering
: the implications for covering and logistics, but then again,
: they may have lived in the Angle, I am merely trying to find
: arguments for and against it so I can determine in my own mind
: where I would consider it advantageous for them to live, and to
: justify them living in The Angle.

But the Angle is the only part of Eriador which is both hospitible to Men and lies 100 leagues outside the Shire. It also happens to be to the east of Bree, which was where "At the Sign of the Prancing Pony" said they seemed to live. The Angle fits all the criteria better than anything else.
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