I fundamentally disagree with the notion that PE rations mean less for tech stocks. Yes, you have to take into account their growth potential, but at the end of the day, a company's value is driven by their profit margins and ability to grow those margins.
So, while a PE ratio of 15 might be low for a tech stock, one with a PE ratio of 60 is probably way out of whack. It assumes exponential growth for many years, which is unrealistic given that major economic shocks tend to happen every 7-10 years.