the LCD-2 is very enjoyable straight out of an ipod. I am not the first suggesting so. They are still really fast and perform really well. Doesn´t at all start to congest or get overly bassy or anything like you can get with other more demanding dynamic headphones.
They are certainly not one of the headphones I would say really require an amp to get close to their max potential. Of course they scale what serious headphone doesn´t but they sound perfectly good out of the Ipod. It all depends on how bitten you are by the audiophile bug I suppose but I would more strongly recommend better amping for the HD 650, Pro 900, T1, DX 1000 then the LCD-2. Though if I would only get one headphone I would chose the Ipod/LCD-2 combo without hesitation.
As for dynamics I feel my 300 mW Head One seem to offer the biggest sound on these. My GHP and V200 surely doesn´t have a problem with it. The V200 has much better power ratings than the Head one. The GHP power rating is a mystery to me but V200s power rating doesn´t translate in a more dynamic sound at the average SPL I want to listen to anyway.
Maybe the story would be different if I listened at 110 db rather then 80 db and 90 db when rocking out