If you're not going to be stuck in an all-inclusive you really, really, really should head for either of these two places:
Montezuma, at the very tip of the Nicoya peninsula - it's about a two-hour bus ride from Liberia and there are direct buses. It's a gorgeous little beach town, populated by ex-pats and some hippies. Tons of hotels, unbelievable beaches.
San Juan Del Sur, Nicaragua - Less than an hour from Liberia. I preferred Nicaragua to Costa Rica while I was down there and San Juan Del Sur has the most beautiful beach I've ever seen in my life - it's another well-visited but unspoiled town, there are tons of hotels to stay at and the beach, my god the beach.
Avoid Tamarindo unless you're into tourists, hookers and blow.
both Montezuma and San Juan Del Sur can be found on this map:
http://maps.google.ca/maps?hl=en&cli...-8&sa=N&tab=wl