What price point favors separates over integrated?

At my point in the audio food chain, an integrated is the only choice. Buying separates for less than $2K total doesn't make any sense. But there are some really really expensive integrated amps out there. Which got me thinking... At what price point is it better to have separates rather than an integrated? I'm leaving out concerns about space here. Just for sound, if you have $5K, is it better to have a Levinson integrated (or equivalent), or two components, say $2K pre and $2K amp (+ cables/powercords if you're into that)?

For that matter, where's the cutoff for monoblocks over a pre/amp combo?

I know there's "no right answer" here, as it will depend on your particular taste in gear, but I'd like to hear your opinions, as many of you must face this choice.