Daniel,
There are so many fabulous places you could spend a day. Here are a few suggestions, depending on what you are interested in and what the weather is like:
The Cotswolds: Broadway, Stow on the Wold and Bourton on the Water all being very picturesque, Bourton also having a motor museum.
Warwick Castle: one of the best examples of a battle-scarred English castle.
Stratford-upon-Avon: William Shakespear and some lovely riverside settings
Henley on Thames: Attractive riverside town
Oxford is fantastic, perhaps the most interesting place to visit, but they hate motor cars, so not easy to find parking spaces unless you use the park and ride.
There are great pubs to be found in or near all of the above.
