headphone amp

Looking for suggestions for a headphone amp that will drive either grado or sennheiser phones (low to high z). Something that retails for under a 1 k $. Have considered the Creek amps and the Grado amp - any experience with these (and what phones wre used with the amps), or other recomendations for amps in the 1 k $ retail and below would be appreciated?
I have no experience with Creek or Grado, but I would recommend in the strongest possible terms to look also at the Yamamoto HA-02. Granted, it will fill out your $1k budget completely, but if it cost twice that much it would still be an excellent buy imo. It sports two small Western Electric WE 408A tubes and is designed for low impedance headphones if I understand the website correctly (Yamamoto-san's explanations are, erm, somewhat idiosyncratic, but then again, my Japanese ain't that brilliant either, so what am I complaining). I am using the amp with Audio Technica ATH W1000 Sovereign headphones (40 ohm). Should you be interested, there is a review by Srajan Ebaen on 6moons with a lot of technical information.
check out the Cayin unit, great tube sound, great value.
Check out www.head-fi.org
How about the headphone amp from Benchmark? http://www.benchmarkmedia.com/h1/. Load impedance is 60 ohms or higher. Supposed to be the same amp used in the DAC1 which I've used with Sennheiser HD600s.
There is no real need to spend that much on a headphone amp to get good sound. I own both Grado RS-1 and Sennhiezer 650HD.

If you need just an amp (no remote) the Gilmore Lite from headamp.com will do the trick for $400. They also sell "better" amps too. If you want a tube amp the brand Single Power is worth checking out.

Also benchmark's DAC1 has a good headphone amp too. It could also upgrade your system's DAC depending in what you own and start at $1000.
"If you want a tube amp the brand Single Power is worth checking out."

NO do not even think of Singlepower! Please read all the threads on head-fi.org about Mikhail's dangerous shoddy engineering and fraudulent business practices. He has disappeared, leaving many customers out $$$ and equipment. While his amps once commanded a stellar reputation, he has been exposed as a fraud and crook.
Don't buy any used Singlepower amps either unless you are an engineer and can redo the wiring.
Do not buy Singlepower! He ripped me off for $6K on the last amp i got from him. they are also hit & miss on the used market. (mostly miss) The remarks "fraud and crook" are being to nice IMO. Stick with offerings from Headroom or Headamp, or Woo Audio.
Lots of info on www.head-fi.org or www.head-case.org
That is pretty sad to hear about Singlepower. I had one of their amps about 10 years ago and thought it was pretty good... Sorry to hear so many people got screwed! Hopefully you paid with a Credit Card and could stop payment.

Headamp always seemed to be more geared toward the Grado band and Headroom always seemed to favor Sennheizer (very general and IMO). I have owned a few Headroom amps and a few Headamp amps and they all were pretty good. I felt that Headamps were better buys but I have not heard Headroom's newest line.

I would argue that you look for an amp to drive the Sennheizers well. Most anything that can drive the Sennheizers will drive the Grados with ease. Keep in mind the Grados are 30 ohms while 650s are 300 ohms. But some amps may be better suited for Grado because of impedance matching.
I heard the woo amps at RMAF and they were very impressive.
If you want to go with Headamp, then go for the GS-1. It's head and shoulders above the Gilmore Lite (I have both) with better transparency and space. It works well with both Grado (I have RS1 etc.) and Sennheiser (I have HD600).