Walking around Khon Kaen during the day and it just looks like any other average Thai city. There are a few touristy highlights and at the start of the evening night markets pop up. After filling your belly with an excellent Thai meal and ready to enjoy some drinks and music you should head over to the area of the Pullman and Kosa hotel.
Just across the Pullman are a few western orientated bars like Erics and Leo's bar. You will find the expats meeting up in these places and the odd tourist. All is laid back and not to be compared with Bangkok but still nice for a good night out. Also visit the German beer bar in the basement of the Pullman hotel. They have 2 large boilers just behind the bar and brew there own German beer! It's tasteful and all is set in a German atmosphere.
About 5 minutes walk from the Pullman hotel is Pracha Samran Road with lots of Thai orientated nightlife. Big clubs like U-bar and Boss Time are on this road. Music is of course very loud and the clientele are mostly Thai in the age of 20-25.