well i think it depends on whereabouts in london you want to end up? personally I would think west is best - as that gives you more options for london bridge, waterloo and charing cross. the thing is, i would try to live fairly near the station you want to be near because the buses are crap and the traffic can be worse so you prob ought to rely on walking to the station.
thanks. i used to live in canterbury - well very nearby and went to school there so i know it well. have you looked at the new builds on the old tannery site? dont know if they are to your taste or not. the good thing about canterbury city centre is that there's tonnes of little 2 bed terraces which are ideal for couples - but if you want something bigger you'll have to pay a lot to be inside the city walls - so to speak.