For the lolly, the AKG 271s's are excellent cans. Also they are pretty reasonable here in the US--check out ebay.
They are accurate, clear, and remind me of good studio monitors, but they do have some warmth to them and pianos on them are to die for. Bass is lean, but I suspect that is so because of how well balanced the sound presentation is with these phones. For closed headphones, these are my first choice. Velour ear cushions are highly recommended.
Amplfying the 271s's is a really good idea. I amp mine with a Decware Zen Head or a Total Bithead for portable applications. My cd player at home is a rather high end beast and has a terrific built-in headphone amp.
For your 300 bucks, you could get an AKG 271s (doesn't matter what series and the 272 is pretty much the same thing) and a Headroom Total Bithead (which includes a DAC) and is a great entry level headphone amp/dac.
But if you are a bass hog, you need another can. AKG 271s sounds great for claasical, jazz, pop, most rock, and is excellent for movie soundtracks.
The AKG 271s is not the headphone for the headbanger, metal head, punk rocker, house musuc, sort of dude or dudette. But there are probably metal heads who love the AKG 271s (like me, but I must confess, for metal I go Grado 325i).