I recently got some Sennheiser hd428's and decided I liked the Sennheiser sound better than the sound of my Grado SR-325is.  I am considering selling the Grados and using the money to purchase a higher end Sennheiser in the same price range. What would you recommend as the best closed...

I have a pair of Grado SR-325is and although I do love them, I recently bought a pair of Sennheiser HD428 and have decided I prefer the "Sennheiser sound" to Grado. I would like to try some higher end Sennheisers. If anyone has a higher end pair of Sennheisers in the price range of the Grados...