Superlux hd660, dont take any notice that im selling a set (i have 2 and am keeping one), they are absolutley brilliant and have caused me to dispatch a ton of gear, combine these with some aftermarket pads for an extra £10 and I cant think of anything better for under £100. The will last forever and and are tuned to perfection for indie and rock style music.
Seriously ignore the fact that im selling just buy a pair even from somewhere else, I think thoman.de have them as well.
Yes they are good but OP said he was looking for something smallish. The 660 are giant and don't fold.