Looking For Mr. Goodgame

My wife and I are going to Paris and Tuscany (the European versions) in May with another couple, and I'm trying to choose three good games to take with us for those times when we're on the train. My wife is not a gamer by any stretch of the imagination (as I've mentioned before), and our friends have roughly the same level of interest. As such, I have a few criteria I need to meet with these games, and I'd appreciate a little help in choosing games from you, my readership.

Here's my criteria:

Small box footprint - This means primarily card games, although I know there are a few games that could be taken "sans box" and take up an equivalent amount of space.

Shorter playing time - Anything longer than an hour is not going to fly. Even better is a game that can be played in a variable number of rounds so that we can scale playing time as needed.

Simple rules - By simple, I mean I should be able to explain the game in three rules or less. Mamma Mia! is a good example, as you play x cards of a given ingredient, an order if you wish, then draw back up to seven, and you try to have enough ingredients in the stack to fill your orders. The rest can be explained as the game goes on.

Play well with 2, 3, or 4 players - There may be times that just two of us are travelling, or want to play anything, so scaling well for a varying number of players is important.

I will be taking a standard deck of cards or two, and that may actually be enough. The other games I'm considering are:

Katzenjammer Blues - Great, and even better with Dave's partnership rules, but I think this is best with four and doesn't play well with two.

Mamma Mia! - Again, not a two-player game.

Money - May be a little dry, theme-wise, but this is one of my favorites.

Bohnanza - Has the huge advantage of being something my wife already knows how to play, but perhaps a bit complex for the friends with all of the trading.

Geschenkt - I'm not sure I can see playing this for two hours, but this is one of my favorites for a quick game right now.

Travel Settlers - This would really be pushing the envelope on several fronts, but I think it could be very popular once people learn it.

Travel Blokus - I've only ever played with four, although I do hear it works for two.

I'll probably end up with one "board" game, two card games, and a deck of cards (maybe a cribbage board as well).

It's a drag that no one else like video games, or else I'd get Dave (the other guy travelling, not the one who used to post to this blog) a Nintendo DS and play Advance Wars the whole trip. Sigh.
Any other suggestions?