[Kabir10]

Hey i am planning to buy new headphones but am really confused as what to buy. My budget is $100 and just want to use it for my ipod. I mostly listen to punk rock, RnB, metallic, etc. Portability is a vital factor for me and also would prefer if the cans are closed ones.

 

[Young Spade]

I'd recommend the AT M50s although they are a bit on the big side.... you want closed to? Hmm... check out some of the Sennheiser cans; those are pretty good for the price. 
 
Are IEMs out of the question? 

 

[tdockweiler]

They M50s are good for the price, but they're not exactly portable. If you don't use Ebay, it may be hard to find them for $100. Shipping would also bring the price up. I paid $125 for mine at a local Guitar Center and felt it was worth it. I just don't like the bass and it gets old really fast.
 
I prefer the Koss Pro DJ100. They're $80 and 6.7oz. The M50s are 10oz WITHOUT the cable, so not a huge difference. If you like the sound quality of the Porta Pros you might just like these. They're much more comfortable to me and I prefer the design and sound quality over the M50s. Some prefer the M50s I guess. Not me!
 
A step down is the UR-55 which more closely resemble the Porta Pro in terms of sound quality, but they're semi-open, so that's out maybe. They're still worth a look though and they're $50. You can demo them at most Best Buys. They're what I'd use if I had to pick something under $80.

 

[Slaughter]

The M50 with coiled cable is very portable. Since the cups swivel you can just keep them around your neck and they fold up in case you want to stuff them in your backpack. The cups aren't very deep so they don't look ridiculous and actually I get a lot of compliments on them.

 

[violinvirtuoso]

How about a pair of Sony V-6 (7506) with Beyerdynamic Pads. Sounds great, is comfortable, and is portable (it folds).

 

[Mr Joboto]

I'd say to look into ES7s.

 

[magicalpig]

Super cheap : panasonic rp-htx7

 

[Kloug]

Consider the Shure SRH440. Maybe a little big but they are closed, foldable and very solid. Among the best sound quality available for $99.