Lucerne, day trip out of Zurich?

Yes, Lucerne is worth a visit. Very scenic city, along a lake- consider taking a boat ride. Also there are lots of Picasso's scattered across the city's art museums. Also home the first class Swiss Transportation Museum. Rick's Switerland guidebook has a chapter on Luzern.

Definitely!!! You could take a boat ride across the lake when you arrive at the train station. Get off at the Transport Museum, spend some time in there (I had enough after 4 hours, kids and hubby spend an additional hour while I was waiting outside at the beach) and then walk back along the lake shore. Walk the famous covered bridge, have dinner at a restaurant along the river ...

I would definitely get out of Zurich and see the Alps and countryside as much as you have time to do so. Do as the others suggested and see the covered bridge and eat of one of the waterside restaurants. I also loved going up Mount Pilatus. We took the cable car up and the cog railway down. For me taking the trip up Mt. Pilatus and walking over the cover bridge were the highlights of Lucern. We also took the boat ride, but we were there overnight.

YES! And if you don't mind visiting a "tourist trap," I can recommend the Stadtkeller for a meal and show featuring yodeling, alphorn players and flag throwers. For better food, you can go across the way to Fritschi (excellent Bauernbratwurst, pilsner beer and chocolate fondue), but you won't get the show. Yes, the Stadtkeller show is put together for the tourists, but it is still a lot of fun and may be your only opportunity for seeing performances of yodeling, alphorn playing and flag throwing. Incidentally, they only offer this during the high season. During the low season, they have live music that varies. They had a blues singer when I was there a few weeks ago. We went to Fritschi instead. :-)

Depending on how much you want to do in Lucerne and the weather (ie - will it be good to go up Mt Pilatus) - you can take one of the scenic train/ship journeys or the fast train - or one of each (fast train back)! Have fun!