Tink, my parents live in Abingdon (we're in Kidlington) and it is very child-friendly, big pedestrianised shopping area in the middle of town and excellent bus links with Oxford. There's a massive soft-play place (Snakes and Ladders) and a lovely leisure centre with a good swimming pool. Abingdon is not a 'buzzy' place - if you want excitement, you'd be better off in Oxford (more of a cultural mix too) as Abingdon is possibly too quiet for some people. However, I think it's a nice place to live, and if your husband has a job there it's ideal. Witney is LOVELY but the road between Witney and Abingdon is a PAIN so I wouldn't bother, especially if you don't drive. Plus there are NO buses from Witney to Abingdon, so you'd be stuffed without a car. If you're strapped for cash, Didcot is close to Abingdon and is much cheaper. Of course, that's because some people regard it as a bit of a dive
but like anywhere, it's got its nice areas and not-so-nice areas! Abingdon also has several very good schools, parks etc.
You're due a couple of weeks after me, so maybe we could meet up with our newborns if you're going to be in Abingdon! I visit it quite frequently