Skullcandy Holua for my iPod touch. Decent upgrade to the default apple iBuds, retail for around 100usd, but I got them for only 15usd off Amazon with a 20usd Amazon gift card which I bought for 10. Overall sound quality is hollow and not very full compared to good earphones, but they got nice bass. The chord is annoying too and poor quality, because it gives off a small amount of constant static and you can hear when tap it.
The real stuff. Audio Technica ATH-AD700s for iMac and/or ps3 while gaming. I use it with an Astro Mixamp and Labtec LVA-7330 and the immense soundstage of these makes for very accurate pseudo surround sound with the mixamp's processing. Widest soundstage I've tested of any headphone so far-- even larger than some 300-400usd Sennheisers. Very bright and full highs/mids, while the bass is tight and punchy, but lacking in terms of actual boom that you'd should feel otherwise. Got them for 100usd off Amazon.