These days, 75-90 mins. for domestic, unless I really know I can get through check-in and security quickly, in which case it's more 45-50 mins. - alas, the only airport I go through with any frequency that qualifies is RSW. Unfortunately, I definitely can't reliably cut it that close at my home airports (LGA, JFK, EWR)...
International, I get there 2.5-3 hours prior to the flight. Sorta international (aka Canada) I get there no later than 2 hours prior.