There are many different flavors of "highlights tours". Here is a thread I started about a "multisport" version that some of you might find interesting.
http://www.costaricaticas.com/phpBB2/viewtopic.php?t=7882 and a direct link
http://www.costa-rica-tour.net/tours/super_combo.php
The more usual ones are variously called "highlights tours", "all-in-one", "4-in-1" (or "5-in-1" depending on how they count), etc. They typically include:
1) a stop at Poas Volcano,
2) a stop at Doka Estates (or simply a stop by a coffee field on the side of the road),
3) a stop at La Paz (or at least formerly),
4) a boat ride (usually about an hour long) on the Rio Sarapiqui to see caimans, sloths and other similar creatures.
5) and a late afternoon return ride back through the Braulio Carrillo Cloud Forest to San Jose
It should be noted that SOME of the tours may have done the lunch part at La Paz, but many just did a walk down the short trails to the waterfalls for a photo opp and back (some didn't even enter the private park but just visited the falls that were publicly accessible from the side of the road). Some did their lunches at a much cheaper local restaurant in Varablanca, Puerto Viejo de Sarapiqui (before going out on the river) or if they didn't do that at the La Selva Lodge and Biological Center before doing a guided walk on their grounds.
IMHO, these tours are an okay option for those who haven't been to any of these places (or similar ones) seperately or who need to cram in a lot of different "mainstream" photo opps in one day so that they can spend all the rest of their days in CR chasing pu*sy. HOWEVER, it makes for a very long and tiring day and, because they try to squeeze in so much into a limited period of time, most if not all of the stops can seem very rushed compared to the time you'd have to spend exploring them if you went to see them seperately (or even on smaller less ambitious combo-tours such as Poas-Doka). If you've made any number of visits to CR, as most of us have, and try to get out of the Gulch as at least some of us do, then you've probably already seen most of the highlights seen on the all-in-1 tour on various other tours you've already been.