I've never been too confident in using VBR cuz I use MusicMatch and their software leaves you guessing too much....

So, I did all my music at 160kps.... I thought it was the "sweet spot" for quality and disk space. But with disc space being so cheap now, it is a mute point. So... for months I've been going through re-encoding all my music. Belive me, it isn't fun. So I recommend no less than 192 (or go VBR if you can get good advice).