I've listened to very few headphones in my time, but I also think that the V6/7506 are a good choice for the usual reasons (bass,small size,looks decent, good sensitivity/volume,good detail/low price). I don't think they're very comfortable, but ordering a pair of Beyerdynamic pads for the DT 250 (I think) are said to help. And quite a few people consider them on the bright side, so that may become uncomfortable during long periods of listening.
In spite of all that, I quite like them, and think they're worth the price. I also have the ER-4P right now, but I'm almost certain to return them. They do sound good, and I don't think they have weak bass, but I don't think I like them enough for that price. Since comfort is an issue for you, consider what canal phones will be like--I don't find them comfortable. I haven't been captivated by their sound like others. But, having said that, I should admit that I haven't listened to them a lot, and you may love them. It's primarily a price thing: I don't want to spend that much on any single thing, unless it blows me away, because I don't want to make this a serious hobby.
And the DT 250s can be had for $142.95 at B&H
, just fyi.