I hope others will chime in with their thoughts too. There are many Flyertalkers familiar with this hotel from the 1THB/night mistake rate from a few years back.

Holiday Inn
If you want Patong Beach, the location of this hotel is fantastic. It's right across the street from the beach. Great hotel with nice pools and walking distance to everywhere in Patong. The Busakorn wing is seperate on the back of the property, with a nicer pool and restricted access to only those in that wing. Although I suspect kids, I don't know that that wing will be 'overrun' (I'll try to sneak in later today and check it out).

They tout themselves as 'Family Oriented' meaning you cannot bring overnight guests that are not registered at check-in.

Mercure
As for Patong with a pool bar. The new Mercure Hotel (accor) is one block further away from the beach, but just opened a few months ago. The rooms are nice, but not quite 4 star, great pool in the centre of the building, and another small rooftop pool make a great atmosphere. I took photos while there a few months back, but haven't posted them anywhere.

Le Meridian between Patong and Karon Beach is a great hotel too, and not too far from either town (5-7min in tuk-tuk, scooter)

As I've always stayed on the cheaper side here, the frequent travellers may have more advice.