The tide is in, so Mont St-Michel is an island again.  For half the day it's surrounded by water, treacherous water only inches deep.  St Michael's Bay is famous for developing pockets of quicksand (sometimes even when the tide is out).  This makes it a very poor place to stage an invading army.  If you're going to lay siege to this town, plan on doing it in four hours or less.  The layout of the town inside the walls provides one opportunity after another to wreak havoc upon any invaders who actually make it over the walls or through the gate.  The first street leading up from the gate is 9 feet wide and steeply pitched.  A dozen defenders with crossbows at the top could turn the bay red.  When the abbey was built in 908 Europe was still in the throes of the Dark Ages and "defense" was a primary consideration.  The Abbey-town of Mont St-Michel was designed by some very savvy folk.
The church for which the rest of the town exists is at the very top of the rock.  In 908 Romanesque was still in vogue: barrel vaults and thick columns.  When extensions were added in later years, Gothic was de trop, so the later sections have the more recognizable thin columns and peaked vaults we've seen so much of in Paris, Rouen, and Bayeux.
The shops in the town below are high-kitsch and you would only buy something there if this were your last stop in France and you still needed a few souvenirs.  The food, however, is outstanding.
Considering everything, this was a delightful vacation.  A favorable exchange rate also plays heavily into that equation.  Although we were shocked at having to pay 850FF for our room, dinner overlooking the bay (with a very nice white wine), and breakfast, the pain mostly goes away when you realize it's only $109.
One charming touch I have so far neglected to mention is that all of the museums and tourist attractions we visited have very elaborate ticket stubs.  The Museum of the Bayeux Tapestry, for example, has scenes from the tapestry decorating theirs;  M'O decorates theirs with miniatures of some of their famous exhibits.  They make wonderful mementos.
Advice for tourists: forget Traveller's Checks.  Bring your VISA and an ATM card (if you can't use the VISA for that).  You will get a better rate from VISA than from any money changer at the airport.  Hit the Internet; book your own rooms; avoid package tours, but when you get to some place take a guided tour of that place.  This is especially true for museums and such.  Eat the local food; they live on it, they've been doing it for ages, and they know how to cook it.  If you're going to stay in one place for more than a few days, consider renting an apartment; jump on the net and search for "rent apartments ... Sydney" (we're going to Australia next year...  unless I can talk her into Vienna).  You'll save beaucoup bux and have the time of your life.
Merci de votre attention.  Au revoir.