Appropriate amp for 225/325 and 580/600 level of headphones

Welcome scdavis0. I previously owned the SR-80s, currently have the SR-325s and the Senn HD-600s. I'll give you a rundown of the amps that that I have, and what, to my ears, goes best with each 'phone. Others here will be able to give you different options.
First off, do you want, or need portability? If you do, the Total Airhead is about the only commercial option available in your price range. In my opinion it is more suited to the Grados than the Senns, which are more difficult to drive. It also has a crossfeed circuit which some people swear by and I swear at! You may also wish to contact JMT or Apheared who are the resident amp builders here and have been known to build amps for people on occasion. JMT has built me 2 amps so far, and I believe they drive the Grados better than the TA. The amps are designed specifically for low impedance 'phones such as Grados.
If portability is not a concern, then I would recommend the MG Head DT, a tubed amp, for the Senns. It's a bit over budget, but it pairs very well with the Senns. Some people love it with the Grados as well, but I find the JMT built amps to be better for my ears. The Creek OBH-11, available for just under $200 is also an excellent amp and does a wonderful job on both the Grados and Senns.
Of course, all of this is just my opinion. The best way to determine which is best for you is, as always, to audition any components you may be interested in. Headroom offers a 30 day trial period for their 'phones and amps.
Hope this helps.

JoeLongWood: Is there a "significant" musical difference between a decent pre-amp and a headphone amp, for use with these headphones (I have the Grado 225s). I haven't bought a headphone amp yet and the very helpful headwhiz kids at headwize suggested the Creek OBH-11. Now, in Riyadh, not much headphone amps are available. Only one, the MF XCans v2, but I was advised that they are not compatible with the Grados.
But there are a lot of good pre-amps here on sale (> US 600) going down by 60%. I could go for the Creek though the shipping cost is around 100 dollars. But is a headphone amp just a very good pre-amp without the other bells and whistles?

I am at the fork of the roads. I need something while at work in the office. Should I go and order from outside a heaphone amp (Creek, most probably) or just buy the rather costly pre-amps here on sale. I have a good pre-amp at home but haven't heard a headphone amp yet. Portability, size are not an issue here.

"Shukran" in advance. (Arabic, for "thank you").

RogerEsq, unfortunately there is no easy answer to that question. Only your ears can tell you if a dedicated amp provides a "significant" musical difference from a pre-amp's headhone jack. I can only tell you my personal experiences, based on what I've heard.
I don't own the 225s, but I do have a number of other high-end Grados (325s, RS-1, HP-1). None of them need an amp to sound good. An amp, though, makes them sound better.
That said, I've listenened using various receivers (Carver, Denon, JVC), integrated amps (Yamaha, Pioneer), and a pre-amp (Harmon Kardon Citation 21). Each one imparts a different sound quality. Some are good, some not so good. Most seem to muddy the sound a bit. But none deliver the clean power that a dedicated headphone amp does. The Creek OBH-11 is an excellent headphone amplifier, and, to my ears at least, does a better job than any of the headphone jacks listed above. It pairs very well with Grados. The sound is cleaner, more dynamic, with tighter bass than the jacks above. There may be (probably are) pre-amp headphone jacks out there that do an excellent job, but my admittedly limited experiences haven't uncovered any yet.
Again, only your ears can be the real judge of what sounds good to you. Hope this helps and good luck.!

scdavis0,

Ain't gonna be me. I totally dig the Creek OBH-11.