For me it takes exactly 14 seconds.
My hardware is pretty fast but I have plugins: Waves 7 complete pack, Line 6 complete pack, Groove Agent 3, Halion Symphonic Orchestra 1.5, IK Multimedia T-racks 3, Sony complete plugin pack (that came with Sound Forge 10). Those are slowing it down a bit (I mean the startup).
Anyway, not too long I think. Some of my projects startup for like half a minute or so.