If you want open back, or the best sound quality for the dollar, I have to agree with the Philips SHP9500. For home though where I don’t mind having open back headphones, I use HD 558’s. To me, I would pick the Philips SHP9500’s over them as they sound basically the same to me, are just as comfortable, but are half the price!
If you want closed back/something to block outside noise, there are actually 2 REALLY good choices:
For the best sound/$, check out the Monoprice 8323 Hi-Fi DJ headphones. They are SUPER cheap ($16), built surprisingly well, removable cable, and have a very balanced sound that is easy to drive. I actually use these at work in the machine shop because they are so cheap that I don’t mind what happens to them, yet are ‘good enough’ to satisfy my taste for all day wearing. Not the most comfortable pair, but they work.
If you want something like the Monoprice 8323, are OK with a super long coiled cable, and want something that is built like a tank with super balanced sound (like for music production), than the Sennheiser HD 280 Pro’s come in at almost exactly $100, and are much more comfortable (for me at least) than the Monoprice cans. I would normally pick these over the Monoprice ones any day of the week, but at work I am in an oily/messy environment walking around, so the replaceable cable/cheap price of the Monoprice won out, and they are ‘good enough’ on comfort and overall quality that I seriously can’t complain!
The current Sennheiser 4.** series are complete garbage. Sound quality is barely there, and they are just CHEAP in every way. There are so many good options out there though, so it is hard to recommend even just a few.