Yup, Poas is the winner. We did CR for 2 weeks around xmas '98 - my son (now the NW pilot) was studying 6 months in San Jose - and we loved it. Saw the northwest (Guanacaste), Monte Verde Cloud Forest, Tobagon + Arenal, and lots more, and then the Southeast, Caribbean coast. What I remember best about Poas were those giant plants along the roadside - they show very well in your photo - and a small fuming lake at the top of an unbelievable shade of blue-green. But I wouldn't discount Arenal, if only because of its proximity to one of CR's - maybe THE - major attractions. the Tobagon hot springs. What a blast they are, all thanks to Mother Nature. We must have spent 4 hours there, until we were prunes.