I live in MK and love it.
We're in Loughton which is nice and is the grid square just behind the station so walkable if you need to. We're about 5 miles (and 11 roundabouts!) from the M1, takes about 10 mins max as it is straight along a main grid route. Only downside really is that there is no local pub nearby
although there are a couple on the other side of the square, one is a harvester type thing in an old pub building, other is old one that has just been taken over so haven't had a chance to go yet. but have little ones so chance of me actually getting to the pub are fairly remote regardless of whether there is one there or not.
Schools are OK; we use one in the next grid square though that is fab, called Glastonbury Thorn which is an infant school which attracts people from all over MK. It's in Shenley Church End, another nice area as are all the Shenley's I think.
Middleton, Downhead Park, Furzton, Grange Park, Oxley Park are all nice - but are all (apart from DP) on the far side of MK for the motorway. Not really sure very much of the stuff on that side of MK.
Have a look on the MKWeb.co.uk site - there used to be lots of useful info on there. and the papers used to occasionally post up lists of which were considered to be the best and worst grid squares which might be available online - MK News and MK Citizen.
I think some of the big estates around the centre and there's also one near the hospital that are best avoided if you can at all, but even in them I think there are some OK bits, there's very little that is very bad. Find an area and then google it especially through the news to find out what is happening in it.
There are lots of new developments and estates being built over towards the motorway which might be worth checking out if you need regular access more than access to the station. Think it is Boughton or Broughton Gate.
There's lots over that side - kingston has massive tesco, costco, climbing wall centre, there's willen lake with play park, adventure climbing in trees, the peace pagoda and lots more parks. In fact most places have lots of parks in MK!
give me a shout if you want more info, if you need any more specifics...