House prices in the Cherwell Council Area are predicted a greater rise than Oxford Council over then next 3-4 years. Bicester's been mentioned which falls within Cherwell - so for this reason alone, I'd be looking here and surrounding villages.
I lived in Brackley, Abingdon and Bicester for several years - commuting into Oxford during the week. As a motorist, I despise Oxford's roads!!
The A34 (grey dirty floor) is disgrace - far too much traffic for a standard dual carriageway. Hit it any time between 7am-9am or 4pm-730pm, it's slow, 50mph through Botley, any crash causes huge tailbacks and that's before you even hit roads taking you directly into Oxford. Parking is expensive, hardly any freebie spaces, the council are so car unfriendly, it's misery getting around.
Problem is that there's not much else on offer except Oxford City Centre for amenities without going further afield (Reading, Milton Keynes, ahem Swindon).
If I didn't need to visit Oxford City frequently, I'd recommend small villages surrounding Oxford and Bicester. Do not consider Rosehill, Barton, Blackbird Leys, Littlemore or the main residential arterial roads close to Oxford City. I'm sure there are wonderful people living there reputations are bad in these places for a reason.