I think it's hard to say which episodes in series 1 are (the only) ones worth watching. Partly because there are various "reveals" thoughout the series but also because in most episodes we are shown a different aspect of the Dollhouse process or ethos and/or of the possible uses of the imprinting technology and how it can go so very very wrong.
I'd say watch them all, if only so that by the end (and in readiness for season 2) you have all the nuances you should have to get what is going on.
Or, if you have to have a smaller list,
definitely avoid episodes 2 and 3, and probably also 5
definitely definitely see episodes 6 7 8 and the the finale
...but then episode 10 has some light to shed on the whole story, episode 11 was a bit slow but explains what is happening in the finale...... Generally, I don't know how interesting some of the twists would be if you've not seen the earlier context, you may have to just bite the bullet and watch them all, there's not that many.