I've been shooting a lot of literary events in the past year--a bit different from concerts, but often in venues with stage lighting or in little clubs, so many of those issues are similar. I use a 5DII, but if you've got an APS format camera, your 50mm and 135mm should be perfect. Once in a while you want a wide shot, if you can get really close or if you want to show the crowd (presuming you've got enough light for the crowd) or if you need a lot of negative space for a magazine cover or a poster where you'll be running text over the image, but realistically, most of the shots you'll end up using will be frame-filling shots of the performers.
If your camera has live view, consider a Zacuto finder. It's indispensable for shooting video, if you do that and don't have a high-end external monitor setup, and it lets you focus stills accurately handheld in a dark club, and if you shoot with live view, you're also shooting more quietly, since the mirror is locked up, which is important in a performance setting.
Here's a Polish detective novelist I photographed a bit over a week ago. The image ran in B&W in the paper, maybe 4x5" on a full-page interview in a tabloid-sized newspaper supplement, in color on the website--
My?le? o czytelniku, nie o sobie -?Nowy Dziennik - Polish Daily News
The image quality of the file I sent them was better--sharper and not as flarey, and had I known they would run it in B&W, I'd have done the conversion myself, but such is life. At least they remembered my credit. As you can see, it was stage lighting with colored gels. I was using an 85/1.4 and shooting probably at ISO 1600. The original frame had the author sitting next to the translator of his novel, but she got cropped out, so this is about 1/4 or 1/3 of the full image area.
To take advantage of the colored lighting, shoot raw, and set the white balance on a calibrated monitor for warmish tungsten--around 2300-2700K. If you're using Adobe Camera Raw, the "fill light" slider is your best friend for hard stage lighting, but if not, you can adjust the curve.