When you buy a Garmin 296 or 396 in this country the unit comes with
TAWS-like terrain for North and South America.

There are two other terrain databases available, which are standard for
units sold in those coverage areas, ATL (Atlantic, Europe, and Africa)
and PAC for Asia and the west Pacific.

These three coverage areas are sold for $295, each, so for someone to
have the world, they would normally have to shell out $885. Yes, you
would have to buy the Americas, too, because once you overwrite it with
ATL or PAC, it is gone unless you have the data file to load it back in.
You don't get the data file when you buy the unit, you just get the
preloaded terrain data.

Well, guess what! Garmin just updated the terrain 2004 data files to
2005 and, for a time (probably a very short time) all three coverage
areas can be downloaded FREE from the Garmin site.

I just downloaded all three and switched between the three with no
problem. I overwrote my included Americas (AMR) with ATL, then
overwrote ATL, with PAC, and finally overwrote PAC with AMR.

Unlike Jeppesen navdata or U.S. manmade obstacle periodic updates, these
terrain files are not keyed to the unit's ID number.

Because terrain changes very slowly, I suspect these three terrain files
would be good enough for a very, very long time.