New to headphones - what amp, source?

There are plenty of portable CDPs with RCA outs, including one rat shack unit (forget the model #, should be able to google it) that was supposed to be a real giant killer. If you want something relatively portable, that is what I would get with one of the Ray Samuels portable HP amps. For characteristics of the all the various portables, try head-fi.org.

Ray Samuels makes excellent headphone amps and his portables are great. However, for portable use, I use an 80GB i-Pod with Apple lossless and Etymotic ER-4P in ear earphones and no portable amp. This gives me great sound and great portability. I have owned 2 very good portable amps that I used with an i-River H140 MP3 player and I must say that it was a pain to have to carry a portable amp around. If you still want to get a portable amp, the Hornet is a good way to go. If you use an i-Pod and a portable amp, the best way to connect them is to use a line dock out adapter with a mini plug because it bypasses the i-Pod internal amp. A home amp rather than portable amp will give you the best sound with your 650's. For portable sources, an 80GB or 30GB i-Pod is a great and very user friendly way to go.

Smatsui gives v. good advice.