A close runner-up is the Springs. It features a dozen cascading pools and whimsically decorated rooms.
No matter where you stay, virtually all area hotels will arrange day trips to the many hot springs pouring from Arenal's slopes, a must while you're in Costa Rica.
On the tip of Nicoya Peninsula, the wide white-sand beaches of Santa Teresa have become a playground for celebrities, jet-setters and vanguard surfers.
You'll need to take a ferry or small plane to the isolated spot (often voted Central America's most beautiful beach), where an array of luxury boutique hotels and condo rentals await.
The fabulous oceanfront Florblanca and Latitude 10 are full-service resorts that won't disappoint.
Costa Rica's most famous beach town is growing up, its scruffy surf shacks and beach bars now complemented with excellent restaurants and attractive accommodations.
Despite complaints that paving the roads and erecting high rises have compromised Tamarindo's authentic local flavor, the surfing is still awesome, and the neighboring beaches of Las Baulas National Marine Park, known for nesting sea turtles, have remained pristine.
Tamarindo's top-end options are well-established, such as the sprawling Paradisus and plush rental properties at Reserva Conchal.
But there are other interesting options, including the romantic Los Altos de Eros, which gets high marks for its attentive staff, and the golf resort at nearby Hacienda Pinilla resort, which sits astride three miles of superb shoreline.
The cloud forests
An escape from lowland heat and humidity, Costa Rica's mountains and volcanoes are topped with misty cloud forests, where temperatures hover between 12 and 20 C (53 to 68 F) year-round and visitors will find a number of outstanding mountain lodges.
Some travelers may want to skip Monteverde, Costa Rica's most famous cloud forest (aka "crowd forest").
Lodges such as Villa Blanca Cloud Forest Hotel and El Silencio Lodge and Spa offer access to quieter, private wildlife reserves.
Others such as Finca Rosa Blanca and Xandari Alajuela are located on coffee plantations and have beautiful trails good for wildlife viewing.
The imaginative Peace Lodge, La Paz Waterfall Gardens is a unique spot with lots of wildlife to watch from gorgeous jungle positions.
An hour from San José and the country's international airport, Los Sueños Resort and Marina is Costa Rica's best value for luxury digs.
Anchored by the graceful Los Sueños Marriott, surrounded by scores of extravagant rental properties, an adorable marina area and one of the country's best golf courses, Los Sueños offers almost everything you'd want from a tropical vacation, albeit without the hassle of actually seeing Costa Rica.
By "almost everything," it's worth mentioning that there's no real beach, hence the spectacular collection of swimming pools.