Chester

Yes, it's well worth visiting, but it's small; two nights is a lot, unless you're planning a day trip. I saw it as a day trip from Liverpool, and this was very nice; I'm not sure what I would have done with more time in the city itself.

One thing I didn't get to is the Lady Lever Art Gallery, on the local train line between Chester and Liverpool (and so, easily and cheaply accessed from either). Another poster here said this was very a worthwhile museum. http://www.liverpoolmuseums.org.uk/ladylever/

Yes, Chester is worth a visit. It was founded as a Roman fortress in the 1st century A.D. It's a walled city so you can walk around the city on the wall, Chester Cathedral is beautiful, Chester Rows are beautiful medieval architecture buildings from the 13th century. There is an Roman amphitheater well worth a visit. We will be there in September.

I think Chester is worth a full day, i.e. two nights. Good cathedral with very good medieval choir stalls. Excellent Roman museum. Walkable walls that surround the center, with picturesque gates and a clock. Streets full of timber-frame buildings. A river runs through it. Hopefully Emma will see this post and give you ALL the reasons why Chester should be at the top of your list. ;-)

Of course this assumes that your whole trip is long enough to take this time. If you have only a few days in England, and haven't been elsewhere, then you might not give Chester that much (or any) time.

Yes, Chester is well a visit. As well as day trip to Liverpool, you could also consider a day trip to Conwy in Wales. Then take a local bus to Llandudno before catching a train back. www.nationalrail.co.uk
http://www.visitwales.com/explore/north-wales/llandudno-colwyn-bay/must-do-in-conwy