Eastgate Hotel or Oxford Spires. Eastgate is 10 quid for parking (read $30 Oz per day) the other is free. Any feed back.
Eastgate is right in the edge of the city, you will hear bells every 15 minutes but not too loud, get a walk in the meadows before breakfast, walk to all sights, handy for river and botanical gardens. Its a fairly old building.
Spires is further out, easy bus ride into town.
Eastgate if you want to be in the centre of town. Very easy walking distance to all sights. Oxford Spires also easy to walk into town (15 mins) and on a good bus route.