USB Audio Interface Recommendation Please (simple, but with good headphone amp)

Hi all,
 
Got a Cakewalk UA-1G a while ago. It's a basic, but reliable USB audio interface. However, I do a lot of tracking/mixing with headphones, and I find that the UA-1G can't drive them well enough (too quiet, relatively high impedance cans).
 
I've got two options as I see it:
 
1. Buy a headphone amp.
2. Buy a new USB audio interface with a better headphone amp in it.
 
I think I prefer option 2. I know nothing about headphone amps, and it's another load of cables and desktop space.
 
Can anyone recommend a USB audio interface, for Windows 7, that is good for headphones? I only need one input, as I'm only ever likely to record a single vocalist at any one time (even then, not very often as I mainly do instrumental electronic music).
 
Any ideas?
Many thanks!
 
[Edit: I have some Sennheiser HD650 cans (300ohm impedance).]

Thanks. I'm heading in that direction the more I look into it. Any recommendations?

All you need to do is take the headphone output and run it to a nice stereo amp. Shut off the speakers and plug in the cans.

That is exactly what I do. My Saffire also suffers from inadequate headphone amp power.  My JVC stereo does a fine job.

benstat

I've ordered some decent headphones (Sennheiser HD650) and I'm going to see how they are with my audio interface, before probably buying a simple amp
 
 
 

I've got these headphones and I think they're totally first rate for listening to all kinds of music ... I suspect you're going to love them.  Please report back on your perception of their efficiency.  Let us know if they are efficient enough to let you stay with your current audio interface?