Biel / Bienne is a good place for what you need.

Equal distance between Zurich and Geneva and on a main train line.
20 minutes north of Bern
Next to the Jura Mountains which means next to France.
The town is the only official bi-lingual town in Switzerland.
Real multicultural society, I like it.

Not a particularly pretty town but it has ALL the facilities and accommodation is plentiful and cheap compared to other towns / cities. Some of the outskirts are nice areas, quieter and countryside and with good bus links to town too, i.e. Brugg, Neuchatel, Maggligen, Nidau.

Dont overlook it in your investigations.