If you've been to your local home improvement store lately, you probably know that there is a dizzying array of caulks and sealants to choose from. But most of these products fall into one of three categories: acrylic latex, kitchen and bath caulk, and silicones or elasto-polymers.
Acrylic latex caulk, designed to fill cracks and crevices in woodwork and moldings, is easy to apply, cleans up with water and, most importantly, it can be painted.
Kitchen and bath sealants are used mostly around sinks and tubs and some of them today come with an anti microbial, intended to retard the growth of mold and mildew.
Silicones and elasto polymers are used to seal up doors and windows and handle other exterior needs. They are really tough and designed to stand up to the sun's ultraviolet rays and weather. In fact, some are guaranteed for up to 50 years.
If you're still confused, read the labels. There's a lot of good information there.