Can only see one.

York because everything there is accessible all of the time and I like medieval sites. Many of the sites in Cambridge are not always accessible to tourists.

I did like Cambridge but I would definitely choose York. It's such an amazing place, e.g. the cathedral, the museum, the shambles. Much to see there.

I love both places for different reasons. I think it might depend on who you are traveling with, the time of year you are going, and what your basic interests are. Although Cambridge is pretty anytime, it is a nice choice in pleasant weather when you can go punting on the Cam and enjoy the architecture in sunlight. York has a great deal to offer, and for me, less dependent on weather to be enjoyable. If you are traveling with kids, the wonderful train museum is there (it's not just for children, though; I enjoyed it thoroughly even though I'm not particularly into trains and it's been a while since I was a kid).

York! For all the reasons others posted. The cathedral is simply magnificent. The Castle Museum is great. And the Jorvik (Norse for York!) Viking Center is fan-freaking-tastic. York.

I love them both and the choice is hard, but I wwould have to choose York. It has an incredible ambience and is my idea of an English town. Love the river and Kings College in Cambridge, but if I had to choose....

Another vote for York, especially if the weather isn't so great.

Todd, My choice is also definitely York! It's a beautiful and historic city, with lots to see. The Railroad Museum there is incredible! Watching an Evensong Service in York Minster is wonderful! Happy travels!

York for me. I love the shambles, the wall, the minster and - maybe I was just lucky - some of the nicest people in England.

YORK for all the reasons given. Neither of us are train people but we spent an entire morning at the rail museum. Evensong at the Minster is lovely even if you're not religious. Be sure to check out the clock w/ moving figures on the L side of the nave as you face the altar (I think it strikes on the hr and half hour) and the spectacular rose window. The Yorkshire Museum is also very interesting, and a walk on the ramparts and/or along the river is nice in good weather. While the Jorvik is kind of Disney-ish, it is interesting.

If you can only see one, YORK. If you can see two, YORK. History abounds, fabulous and famous tea room reasonably priced, good shopping, and Vikings.

I always thought I could happily end my days in York.

Thank you, every one for the comments. York it is.