In case of my SE-5 (which might sound like the original one), HD800 are noticeably more forward and brighter.
I haven't heard, but looking at the graphs, Fostex TH900 should be somewhat brighter as well, and more forward, but less than HD800.
LCD-3 should be similarly dark as LCD-2, so that's the actual match in this regard.
Bass on SE-5 should be closest to the Fostex TH-900 one (meaning slight enhancement). LCD-3 and HD800 have no enhancement.
Thanks. A resolution better HD 800 or SE-5?