SR-225 or ES7?

225 with amp, without amp, under any circumstances...

Yes, under any cir-s higher Grados will sound better than 225.

If your wallet are happy go for them, if you wanna value-just buy 225.

Never look on freq. response it means nothing other than marketing "figure" that must increase along with price.
Some cheap Sony cans have 5-80khz freq. response or something like that, yet they're bad.

And FWIR, the GS1000 does require an amp to really make you feel like you're listening to $1000

It depends on tolerance. Most cans will do 20-20000 with 10db tolerance... In a word, don't think about it.

Any great can require "amp" to sound it absolute best. But even without it, they will sound superb.

I think you're becoming too technical with the specs, and are thus losing touch with the ideal of wanting to listen to music the way you want to.

Synergy is really all that matters for a great system, and even then that is subjective. Just look around and search, and you should be able to get an understanding of what peopel like to hear their Grados with (*coughtubescough*).

And for the record, I've listened to (and owned, except the 325i) all the "main" Grado models, and I prefer the SR 225 as the best bang-for-buck Grado. The pricing is very reasonable (especially used on these forums), and the sound it offers is leagues ahead of the SR 225 and is a very tangible hint as to what the RS-1/RS-2 offers.