I agree with those who say don't overdo it. In most cases, I only fully stat out major NPC's.
For example, I just ran a session where the PC's where poking around a castle. Inside were:
-A whole lot of goblins - went straight from the SRD
-4 shadow-human rogue NPCS - these had stats rolled up, HP, BAB, Saves, Init; all identical.
-1 shifty, old goblin stablehand - standard SRD goblin.
-1 Shadow-elf monk- statted up except for skills. If it came up, I'd assume maxed out tumble, jump, and balance, little of anything else. I'll eventually stat her up all the way, as I expect she'll be a major recurring NPC.
-Several other NPC types, mostly just stats, HP, BAB and saves. They'll eventually get fully statted, but they weren't too likely to be necessary for that session.
None of that took much time.