Location: Australia, could import from overseas though.
Budget: Budget is not a constraint. I want the best quality available.
Design: Bass headphones to use for gaming and music. I want an emphasis on low frequency sound quality. I am using Logitech Z623 2.1 speakers at the moment, but I want headphones that can better or equal the bass quality of them.
Comments: I don't want to spend under $300 unless they outperform the more expensive headphones in bass quality.
What types of music do you normally listen to, (post links) and what games do you play?
For specific artists and games, have a look at my profile. I want high quality bass for electronic and classical music and ambient noise, music and sound effects in games.
The V-Moda M-100 is king in terms of closed-back, very bassy headphones. It rates in at about 32ohms, so you don't need an amp, (though having one is always helpful) and should be driven by just about any device. If you play a lot of competitive FPS, especially counter strike, then these are not for you, as they don't have the best soundstage. Also, they will not be ideal for Classical music.
The Hifiman HE-300 is an exceptional open air headphone that still deliver plenty of bass, and a warm, lush sound. They should still sound good with electronic music, and will be amazing with just about all other genres, especially game soundtracks and effects. These rate in at about 50ohms impedance, so you will need an amp or soundcard, however, 50ohms isn't that high, so a cheap one like a fiio E10 will suffice, though you can't go wrong with a higher end setup.
Pretty much what warpig said, vmoda m100's are recommended if you like bass, although the somewhat cheaper lp's and/or lp2's are usually recommended too. Old sets of audio technica ath m-50's (the ones that came in a blue box I think, correct me if im wrong someone) were also apparently good for electro music, although they're a little hard to find these days. I recently managed to get some v-moda lp's off amazon for a third the usual price, was a steal :)
If you really want to spend loads to get the best possible, then the m-100's are probably a good idea.
Headphones can't really compare to a real subwoofer (if you have ever listened to one.)
Are you looking for a specific style of headphones? In-ear, on-ear, or over-ear? I prefer over-ear personally since the other two types drive me insane. But Sennheiser has a pair of in-ear headphones (IE-80s) that are around $300. Each bud has a dial on it that adjusts the frequency response (crank it for more bass). Linus did a really good review on them. He said when he cranked the dials all the way up, his head felt like it was vibrating and it was "unlike anything he's experienced." Aside from the awesome bass, the mids and highs are supposed to be exceptional as well. I've read some reviews in the past and a few people said to pick up some after-market foam pads since they're comfier and allow the bass to pour out more. Lastly, they aren't going to need an amp, even if it may help a little bit. I believe they're 32 ohms, so pretty much anything will drive them just fine.
But obviously, if IEMs are not appealing to you, then the V-Moda M-100s are probably what you'd want. They're supposed to have soopa bass. Plus their build quality is excellent and they just look totally bad ass. Their sound signature definitely isn't to my taste though, otherwise I would have probably picked them up. Instead, I got the Beyerdynamic DT-880s (250 ohm), which I'm waiting for. They're supposed to have a more neutral sound stage, but with sparkly highs. Yummy.