Help me decide between a portable or full sized amp

Hi there,

I am thinking it's finally time to get some amplification going for my headphones. Right now, I have the Denon D-5000's, and I have plans for getting a pair of custom IEM's at some point in the distant future. My reason for getting an amp is not simply to go louder, my iPod can drive my Denon's plenty loud, as I'm sure they'll be able to with IEM's. I simply feel that running D5000's out of an iPod isn't fair and that there is still a lot more to be extracted out of these headphones.

At first I thought that a portable would be the obvious choice - this way I'm prepared for the future when I get my IEM's, and providing I get a good portable, it will help the sound of the Denon's.

But I'm having second thoughts. My budget is in the $300 range.. for portables that really isn't that great, but for full-sized amps I could probably snag a used PS Audio GHCA for that price. Maybe it would be best to get a full-sized now, and then when I'm finally ready for IEM's I can look at buying a portable for a more decent price since I won't be needing to drive the D-5000's off it.

What do you guys think?

I don't really need recommendations on specific amps, I've got plenty of options in mind. 

What I'm having troubles deciding is whether to go portable for full sized.

Well thanks I appreciate the input!

I came across a thread in the portable amp section thats dedicated to the discussion of portable vs full sized setups, so I re-posted my initial post there. I'd appreciate it if anybody looking to add their input could answer my question in that thread instead.

Here's the link: http://www.head-fi.org/forum/thread/374155/leaving-portable-hifi-it-s-too-silly/690