With the electoral college it's only an important election in a handful of states though. I live in Illinois which is hard blue and don't feel the need to pull the lever for the disaster that is Hillary Clinton. In those states which are firmly red or blue (the majority) you can think more seriously about third parties or not voting without making Trump any more likely.
I'm not a fan of the Green Party really, I think it's a poorly run opportunist party that distracts from more important goals, but if they get 5% nationally they get public campaign funding. Depending on how much momentum Stein can get that could be a goal worth working toward.
The Reagan-Bush-Clinton-Obama neoliberalism has destroyed the country and has come under fire from both left and right, and it will not be able to hold power for much longer. Defeating Trump is not just about this election, but about the future Trumps that will emerge 4, 8, and 12 years from now. Those efforts to fend off future fascism need to start now, and while I prefer focusing on popular movements and building institutional power through unions and the media, it might be a good use of your time to consider Stein, depending where you live and how her campaign turns out.
