My understanding was you need to hold for two years for the discount not to be taxed as income.
I'm in the same boat. Yes the logic everyone will tell you is sell right away, but that's reallllly hard for a stock doing so well.
I just sold $25,000 of my company stock that was $4,000 cost basis (at bottom of market recession...), in using the money to fund a basement remodel. The annoying thing is selling that much pushes us in to the Obamacare extra capital gains tax, so cashing out even more would be a massive tax bill.
I did at least make a small change this year. I turned off automatic dividend re investing, so that'll be $5,000 or so a year less compounding in company stock. And I'll sell enough company stock to fund my ROTH IRA. With those two things though the stock account will just keep going up though. However, if it does Enron I will be hurt but not totally screwed, it's *only* 15% or so of my net worth (way higher than recommended, but if it went to zero I'd be fine). One of my best friends also has his wife work there, they both buy and have never sold, and their ONLY not 401k money is company stock, so 60% of net worth probably. It's worked out GREAT for them so far ...
But. Do as I say, not as I do. Diversity all yours...