Honestly, <'s best job opportunities are here in London. And < absolutely loves everything about the place - the grime, the people, the mix of cultures, the white skies. But it is horrendously expensive, everything from rent to travel. Travel is actually cheaper than most English cities, but because London is so big we need to do a lot more of it than others. Plus, rich tycoons are buying up lots of land to the extent that precious living space is being allocated almost exclusively to that market. < is lucky to have been raised here and therefore have a guaranteed home if things go pear-shaped, as they have.
So that ^ and ^^ know for their flatmate adventures, the cheapest areas are in the southeast - < would recommend Charlton as a nice, safe place with a comparatively cheap cost of living.
Cambridge is an absolutely lovely city though.