Liberatos Village looks beautiful on the outside and has a stunning views - it should have it take 15 mins to climb up to it from the road - and it's a hard climb! It only costs 5 eros to take a taxi up any time you go out and I would recommend you do this. If you hire a car you'll find it will only take this hill in first gear and coaches can't get up it so you'll probably have to change from your airport coach to a taxi - as we did.
Lassi is a beautiful resort with a good choice of restaurants (and I would especially recommend Nefeli's Restaurant for a wornderful choice, excellant friendly service and good prices). The beaches are lovely. You should hire a car to see Kefalonia properly - if you've got a good head for heights! We used CBR for our car hire. Brilliant service, contracts in English and it does exactly what it says on the tin. Nice cars, no hidden extras. They also arranged our excursions. Good prices and good service.