I would have to say my favorite would be an H-555. I think their semis are great, and I like the extra appointments for the 555 (bound f-holes and headstock, nice inlays, multilayer binding on the body, gold hardware, ebony fretboard). A nice 5 piece neck would be a plus, although a mahogany neck is fine. Early ones had maple necks. I've never compared a maple vs mahogany neck, so I can't really say which I would prefer.
Alas, I have to suffer with a measly H-535.... life is cruel sometimes!
BTW, I have a 525, and it's REALLY nice. I liked the sound better than the 575, which always sounded "boxy" to me. The 575 is probably much better for jazz, but for what I play, the 525 sounded better. I'm not a jazzer. LK got this one from Kuz, and when I played it, I told him that if he was ever going to sell it, let me know.