Comments/Ratings for a Single Item

Either Shogi - the drops along with the slow moving generals make this a
very gradual game, yet with plenty of exciting attacks - or Chu Shogi - a
complex Shogi variant without drops, but lots of interesting pieces and
very rich.

I could see myself playing either of those for a very long time without
becoming bored... (as long as the hypothetical desert island includes an
opponent of a suitable level).

Or, if it has to be a variant of western chess, I quite enjoy Parker's
Dragon Chess (not to be confused with Gygax's) - it is very close to
normal chess, yet different enough to feel like it offers more
opportunities, and unlike the various variants adding Capa compounds, the
dragons aren't overly powerful.

Perhaps for sheer variety, Navia Dratp would be a good option - 44
different pieces, and build your own army, allows for a lot of
possibilities.

Of course, given that one of the things I enjoy about chess variants is the
sheer variety - encountering new ideas, having to think in slightly (or
radically) different patterns - being restricted to just one variant, no
matter how good, would be dull compared with exploring the richness of all
the weird and wondrous variants people have invented.

Some candidates are Nightmare Chess, Shogi, Kamikaze Mortal Shogi, and
Gross Chess. Nightmare Chess has a lot of variety and is a lot of fun to
play, but it lacks the perfect information element and doesn't provide as
much opportunity for deep analysis. Shogi and Kamikaze Mortal Shogi have
much the same appeal. I might choose the latter over the former for being
my own game. Gross Chess is my largest variant, and it includes a greater
variety of pieces, including all the Chess pieces plus several popular
variant pieces. Consequently, there is more to pay attention to than in
most variants, and the opportunity for deep analysis is greater. As long as
I couldn't play other games, I'm inclined to choose Gross Chess.

http://www.chessvariants.org/other.dir/rococo.html
Rococo. I think Peter Aronson took offense when I said Rococo rules above
are not well written. I just think the rules should begin with the simple
statement, that they all move like Queens. That's what happens with
collaberation in books too. Combining styles of two authors or more leads
to mixed results in write-ups. Usually two are worse than one in creative
or scientific writing, not always. Still Rococo is the best CV under CVPage
auspices as a game. Rococo Pawns that's why firstly, and secondly the
border squares. Where are either of those two elements elsewhere used? Nowhere
important because they fit Rococo.

At this point I prefer just plain old chess (orthodox chess) or fischer
random. 
 I have not found any chess-like game on this site whose gameplay is
comparable or exceeds them.  

Perhaps its just the huge volume of literature available or that is the
most developed that makes it this way ...but there is no way I want to be
stuck on a desert island with a chess game that is too far removed from 
orthodox chess  .. On the other hand ...a 10x10 chess board with extra
pieces can still be used to play vanilla chess so this 'desert' island
theme cannot be taken literally.