headroom is a pretty good site, as are the forums you get to from there, although probably more hi-fi than studio biased.
I would say any of these would do you:
- Sennheiser HD 600 or 650
- Beyerdynamic DT 880
- Beyerdynamic DT 770
- Ultrasone PRO 650 or 750 (or possibly DJ1 Pro)
Haven't heard any AKG's. Haven't heard the 770, but have heard good things, and it's closed. Bass is supposed to be a bit hyped, but I never understand how headphones can produce a really accurate bass with such small drivers (although some can do so pretty well).
Both Senn's are open, some pretty well respected people use them as a second monitor. Very detailed.
Beyerdynamic DT 880 likewise. I want a pair of these.
Ultrasone 650 I have a pair of. Some people are not keen on these, but I find them pretty detailed, very comfortable, pretty good imaging, and closed. Best pair of closed phone's I reckon (well, 750 are better, but pricier), with DT 770's the nearest competition (hell, might even be better, since I've not heard them). I know some who know's a hell of a lot more than me who is happy with the DJ1 Pro for production, so I suspect they're pretty accurate too.
The bumps you get at high frequencies are related to the funny shapes of your ear canal, and the fact that headphones are pointing directly down it, unlike any sound you hear naturally. They should ideally cancel out to zero, but are not proof of wackness as they would be for if they were the freq chart for a monitor. Of course, charts only show partial information (e.g. not how dynamic a 'phone is, how well transients are dealt with) so you really need, if possible (and it can be hard) to listen to the ones you want to try.
Most mixing engineers of any experience will fall between, "use with a little caution, check on monitors" to "tracking only", and they probably know better than me. But I will say that for £150 spent on headphones, you can get much truer (like, so far beyond that it's a joke) sound than from a £150 pair of monitors (I don't think you can get monitors for that, I certainly wouldn't want them), and you wil not have to worry about the sound of your room.