What are yesterday's rock stars up to today? More importantly, how do they look? Ever curious and nostalgic, we decided to check in with Trent Reznor, Billy Corgan, Chris Cornell and some of our other favorite '90s alt-rock superstars to see what they're up to these days. Many have weathered the years much better than you may expect. Others, well ... scroll through our list of '90s Rock Stars Then and Now and see for yourself.