I've been lap swimming regularly for fifteen years, so I've swum in just about every lap pool in Canberra. Here are my recommendations based on what each pool does best.
Kingswim centres are located all around Canberra (and Australia) and have extremely warm air as well as warm water, which makes them the best for babies - who are extremely well catered for with $4 Baby Play sessions for 3-6 month olds. These centres even have an underwater photographer visit sometimes!
CISAC Clue Blue in Belconnen has the coolest pool (and waterslide) for kids - just be aware that you do need to pay for parking, and for kids aged 2 and up. It also has good stuff for teens.
Dickson Aquatic Centre has a huge range of facilities (although I've found that kids under 3 get very cold even on an extremely hot day) including a Splash Park and two kids' pools. It is the best outside facility (Woden also has an outside 50m pool with nice trees all around the facilities).
Gungahlin Leisure Centre has a splash zone too - but it's inside.
Canberra Olympic Pool has high-dive boards as tall as 5m - definitely not for the faint-hearted!
Lakeside Leisure Centre has a barrier converting its 50m pool into two 25m pools, making it feel less crowded (it's nice and quiet on weekdays during school time).
The AIS Aquatic Centre is very rarely crowded, and if you buy an $88 card it's cheap too. Parking is free (but a kilometre from the entrance) and swim hats ($3 at the desk) must be worn.
The Active Leisure Centre in Wanniassa has a big focus on aqua classes.
