Sennheiser HD25 - i THOUGHT i was getting a huge $100 deal on a pair of HD25-1s, not knowing it was a completely different headphone with virtually no bass to speak of. B&H photo gave me a no hassle refund, but they really whet my appetite for their (stupidly, almost same named) bigger brothers because they had REALLY nice effortless sound except for the lack of bass, were extra comfortable, light, and virtually indestructible. i really liked their styling, though i would have preferred a solid soft plastic headband. it was really disappointing sending them back as i'm just not ready to spend $200+ on headphones yet. they really made me sad i just can't afford hi end cans, and HD25-1s are probably what i'd get because they're high efficiency and have a reputation for bass. i've already experienced their ergonomics. HD25s were such a tease to own, shy the extra -1 at twice the price.
AKG K55 - impressed me for some reason at the music store where i bought them, but after living with them, i grew annoyed with their lightweight sealed plastic sound signature and especially for how painful they were to wear for extended periods of time
Samson SR850 - actually, a VERY nice sounding, cheap headphone i got along with a FREE large diaphragm mic, but was always annoyed that they lacked bass big time, had terrible isolation and too long of a cord as i bought them for portable use, and they had really low efficiency. they'd really make great studio/broadcast headphones, but just aren't bus ride/dance music friendly.
$20 JVC "extra bass" headphones. i had to take them back the next day and exchange them for the sonys because their poorly designed headband dug into the top of my skull making them excruciating to wear
Sony MDR-X150 i have issues with sony spanning a bunch of products and only traded to these because i absolutely needed headphones, and the only other over the ear ones i could find locally were over $50 with no way to audition them, unless they were crappy $200+ beats. i made sure to try them on BEFORE buying them, but they lived up to their price point as low grade disposable junk that went dead in under 6 months, and continues my experience with sony gear breaking. i had a CD walkman break within a WEEK of its 90 day warranty when the bearing in the CD clamp popped out so it could no longer hold discs and got sony's typical "it sucks to be you, thanks for your money sucker!" when i WANTED to buy an impossible to find panasonic instead.
since then, i bought a used pair of presonus HD7s whose headband recently shredded and just bought a NICE pair of superlux 681 EVOs to replace those and am VERY happy with my $40 purchase! they have possibly the deepest bass and best sound of anything i've ever owned, save maybe the bassless HD25s i had a week, have a 3 meter swappable cord making them much more portable friendly than MOST serious cans, extra velour pads i might swap some day, seem reasonably durable, and despite a little bit of extra clamping force, aren't uncomfortable even wearing glasses as it gets distributed across the large "AKG pads" and i like the simple understated design, though i'd prefer losing the gloss & chrome. i'm quite happy with my last headphone purchase and feel no pressing need to upgrade, and their sound only gets better as i've put a dozen hours into breaking them in so far.