Audio Technica ATX-M40x. These are over the ear headphones so they are big, however extremely comfortable (I wear them to sleep!). They have very high reviews, I did my homework before buying them. Pretty cheap price at $79.99, a pair of Beats headphones would cost you 2x as much and sounds absolutely terrible (very bad ever since Apple bought them from Monster). Only thing is the cables that are included (coiled and non-coiled) are very long because they were meant to be used for studios and professional use, so I have to tie it up. Combine these headphones with the V20's HiFi DAC, you get eargasm. I actually was thinking about the Sony MDR7506 as well (which is a very good headphone as well), but after I saw a side by side comparison with the M40x, I ended up choosing the M40x and was glad I did.
If you want a cheap, yet very good headphone, I recommend the Sony MDRZX110. I use it for the gym when I work out, and it sounds very good for the price. Actually sounds better than Beats headphones. Costs around $10-15, you could probably find it at Ross, Best Buy, or Amazon/eBay. I bought some overstock ones for $8 on eBay.
If you're looking for some VERY good home PC or theater speakers, I recommend 2x of Mackie MR mk3 speakers paired with a Polk Audio PSW10 subwoofer. No need to go to the club or to a concert to listen to good music. Connect it to my V20 and it feels like I'm actually there at a live performance!
If you're looking for a good Android audio player, I recommend BlackPlayer EX. Very easy, simple interface with lots of custom options including equalizer and smart settings.