Lion Nathan is hardly a local company, however you support the heads @ thebarton.. coopers is a local company...
whats your faves in thailand glock??
singha? tiger? chang? i forget the other ones, i know tiger is singapore, but its very popular there, also its a nice lager.
Ah I forgot they were owned by a multi-national. Stuff 'em them!

Coopers is great for staying family-owned, it was awesome how they rejected that takeover a few years ago.
As for Thai beers, Singha all the way for me. Great, solid taste and refreshing enough to help with the heat. Though I must admit I'll often drink it Thai style (with ice) these days if I'm out. I know, it's ghey, but it's better than warm beer which happens so quickly in this heat. The watering down effect of the ice makes it even easier to drink in the heat plus has the effect of prolonging your drunkenness, which is nice given the way I'll usually drink (at full speed)!
At home it's straight out of the bottle or a frosty mug though.
I don't really like Chang much at all, it's too heavy to drink a lot of, there's a reason why people refer to the dreaded "Chang-over" in reference to drinking a lot of it and that's one reason why I dislike it. I also don't like the flavour as much as Singha.
For something really light I will go with an "import" San Miguel Light, which is a low carb and very easy to drink. And yes, it is actually improved with lime in it so that's how I'll drink it...
Tiger is not bad, I'll have some of that on occasion too.
Beerlao is another nice one from around the region, like Chang I also find it a little heavy for long sessions though.
The Heineken here (locally produced) is filthy though. I have no idea why so many expats drink it exclusively when Singha and other local region beers are better and cheaper. It's nothing like the nice version in Australia (even though that is also not authentic, it tastes decent).