There are a lot of fans of separates around here, enough that GE came out with the Triton 5 to cater to them. Me, I had separates before my T1s (I got my first sub in 1989) and IMO having the subs designed in was a huge get in sound integration, quality, and imaging. It's to the point now I don't really think of them as a two-way system mounted on top of a sub, but rather as proper full-range speakers in the spirit of, say, the original Klipschorn. Whereas that ground-breaking design used clever acoustic engineering for its bass section, the Tritons use clever electronic engineering. But the result is the same: great, fully-integrated sound.
Keep in mind my rig is used 80% for critical music listening, and that mostly classical. I'm the maniac who gets annoyed because he can hear the clock in the kitchen tick over the soft parts, and then goes chasing down loose picture frames during the loud ones. Often during the same symphony! I'm also a very big fan of room treatments and digital correction. I can't help but think folks who are into separates have listening habits quite different from my own.
Also, don't forget to embrace the power of "and." My current situation is such that the only place I could put extra subs would tick off my neighbors even more than I already have, but when I finally get myself a free-standing house I am planning to supplement my Triton 1s with at least one, maybe even two, freestanding subs (I've sat on a Definitive sub when I could've sold it precisely because of this plan.) Mostly just to see if the separates camp has a point or if they're full of crap. I think it'll be a little of both.
Anyway, that's my opinion and my experience. Counter-opinions will I'm sure be found below in short order