Sennheiser HD 215 by kojak
(There was no "headphone" category so I suppose any headphone could technically be considered a monitor of sorts.)
Sennheiser's HD215s are not neccesarily a studio piece per se, although they do make for a good comparison set of cans as well as being very useful if you're doing hip hop or electronic music.
Despite being marketed as "DJ headphones," I have found these phones to be more accurate than most cans in that category (ie. Beats, etc), and to my ears, are not as hyped as some others in this area. They are by no means reference level, but they are quite robust and will survive the rigors of the road (I've had mine for over 4 years, including almost a year of nightly use as a DJ, and travel to more than a dozen countries).
One feature I have found invaluable is the swivelling right ear...originally intended for DJ use of course, it's also handy for vocalists who like to have one ear off in the booth (as well, the pivoting nature of the headphones allows the side that's off to remain somewhat "attached" to the side of the head, thus lowering headphone bleed into the mic).
The other feature of these phones that I'd love to see in more models of headphone is the detachable cable coming off the left side, meaning a) you can attach a longer cable if need be and more importantly b) if you step on it and accidentally tug on the cable, it will simply pop out and not damage your cans.
So in short, these will serve you well across a variety of uses, including regular daily use, but at the same time are still of high enough quality for tracking in a session. For serious mixing or accuracy you'll of course want something higher end, but for the money, these are a great way to go.