I have the CIA VHP-1, along with the VAC-1 power supply. I like it a lot. While the VAC-1 pushes the price above the $350 mark, it makes significant improvement in performance, especially with hard-to-drive headphones. You might be able to pick up the pair for around $350 on the used market.
I also have and enjoy the Meier Aria. This was a limited edition, and may not be available new. But used, they were going in the $350-$400 range. It has the advantage that it includes a USB DAC and a crossfeed switch. I'm embarrassed to say that I've never compared the Aria directly to the CIA VHP-1 (mostly because the Aria lives at work, hooked up to the computer), but both have proven to be very enjoyable.
You should ask around on Headfi.com, although you'll receive about a thousand recommendations (some of which have a flavor-of-the-month feel). Some of the suggestions, though, seem to weather the test of time. Look into the Headamp Gilmore Lite (which seems almost indistinguishable from the CIA VHP-1 to many reviewers), the Woo Audio 3 (if you like tubes) or the Millet hybrid.
There's another alternative, if you're prepared to do a little work (and if you have convenient headphones). If you are able to separate the ground wires from the left and right headphones, then you can use a sonic impact T amp (or the super-T) as a headphone amp (with some minor modifications). Just don't try to tie the ground wires from the two headphones together as the T-amp doesn't like this.
Good luck in your search.
Chad
