I always used to find 192 CBR was sufficient, but there are some bands whose music seems designed to cause artifacts even at that bitrate

Two examples which spring to mind are Muse and Pantera. I guess it's because they have stuff happening from very low to very high frequencies and 192 just ain't enough - you get jangling and pre-echoes. For some Muse tracks I either had to go to 320 (which gave me HUGE files) or go VBR, so that's what I do with everything now. It just ramps up the bitrate to cope with the complicated stuff.