For me, the R10s and L3Ks are the perfect combination; the strengths of one compensate for the weakness of the other. The R10s are the most musically refined headphones I've ever heard, with an enormous soundstage, gorgeous mids and highs, and the most tonally "right" sound I've ever heard with classical and jazz. However, they have always been somewhat light in the bass and take a more relaxed, distant perspective to the music.
The L3Ks are the opposite; they aren't refined, they're meaty, crunchy, in your face, brawling headphones. When I want to hear the chunka-chunka of guitars and physically feel the THWAK! of a drum beat, there's no headphone that delivers like the L3K. Not to mention that for live rock concerts they give you a front row feeling. Oh, and of course the bass is rightfully legendary... it's the kind of bass you can feel in your bones. However, yes, they are too congested and closed in for large, complex classical, and while they're good on vocals, I prefer the R10s softer presentation.
So I basically use the R10s for classical, jazz, and vocals, and the L3Ks for pop, rock, and metal. I think it's rare that anyone finds a headphone that can do EVERYTHING for them, so I'm thankful I've limited it to just two. The inflated prices of both phones are the only reason I'd even consider selling mine... well, that, and maybe if I eventually get to hear an SR009 and decide I like it just as well; but, knowing my preferences for the more musical side of high-end audio, I'm thinking I'd end up preferring the R10s/L3K combo by a wide margin.
