Ever since 2001, you wise readers have picked Reid Park in this category, and there are innumerable good reasons for that. Actually, there's not just one playground area at this sprawling midtown park; there are several, with all sorts of cool stuff in between (like a duck pond, numerous benches, picnic armadas, a rose garden, an outdoor "performance center," and soon-to-be-ex-spring-training baseball fields). To find one of the larger playground areas, enter the park off 22nd Street just east of Country Club Road; there, you'll find all sorts of colorful, fairly well-maintained equipment for kids to climb on, run across and slide down. Good times!
Runners up:
2. Brandi Fenton Memorial Park
3482 E. River Road
3. Himmel Park
1000 N. Tucson Blvd.