The area from Tweed Heads to north of Byron Bay could, with the greatest respect, be called the retirement zone of eastern Australia. Don't let that put you off though - having just returned from Kingscliffe let me tell you, these old folks know what they're doing.
Unspoilt beach, a lighthouse nearby, good fishing spots, excellent pub, even better bowls club, well-stocked second-hand bookstore and the best coffee I have ever had in my life - Kingscliffe has all the trappings of a trendy beachside town, like Noosa for example, but with none of the pretence. Although if you do like a bit of pretence, then Salt Village, just down the road, should give you what you need.
Salt is a self-contained resort village - accommodation options include Peppers Salt Resort and Spa (fancy!) and Mantra Salt Beach (less fancy, but still really nice). Also onsite are a number of restaurants (e.g. Thai, Italian, fish and chips) as well as a few cafes (e.g. Saltbean Espresso Bar - home of the aforementioned 'best coffee ever'), some shops (Witchery and Sunburn) and a pub with ocean views (an essential for any beach side town/resort).
There are also lots of activities for those who like to exercise on holidays (apparently these people exist), such as bike riding, tennis and various water sports. For the sane ones, there are day spas and pamper packages to fill the time between meals and cocktail hour.
Venturing down to Kingscliffe proper, you'll find a great, old-style pub that has recently been renovated and is only outshone by the biggest (and busiest) bowls club I have ever seen. There are also plenty of cafes and shops, as well as markets on the weekends and, most importantly, a beautiful, uninterrupted coastline.
After spending a little bit of time in Kingscliffe and Salt Beach, I couldn't help but wonder whether all the retirees moved there after retirement or whether they went there for a holiday in their 30s and just never left: why would you?