The Grados are pretty good without amps, but I would get the SR60 or SR80. Especially the SR60 is a great value. The SR125 and 225 are just treble boosted versions of the cheaper ones, in my opinion, and unless that's what you're looking for, aren't as good as the 60 or 80's. The Sony V6 is a good value for a closed phone, again for way less than $100. I'm not familiar with the Sennheiser HD495, but if you get an amp the HD580 is a great phone. I've also heard bad Sennheisers and bad Sonys, so unfortunately you can't go by the brand name.