i really need good headphones for recording and i would like something under 150. i was looking at sennheiser. anybody have experience with them?
For tracking I use Sennheiser HD280 Pros but they are a little bulky for long use and thats where my Grado Labs SR80 come in although they leak sound a lot so you cant track many vocal parts with them...

For mixing songs you really should get yourself studio monitors. You should be able to find a pair of KRK RP5s for cheap on ebay and they sound great for the price.