Does an integrated DAC/Headphone amp exist?


Im looking for a cost effective way of having decent sound and work. Loudspeakers are out of the question so headphones are the ticket. I was wondering if such a device exists as to not take up too much space on my desk as well as limit the cost of cabling. I would like to keep the cost under $1000 for the headphones, cabling, DAC and amp. I want somthing that is musical and easy to listen to for 8-9 hours a day and I prefer over the ear style 'phones and open air designs as to still be able to communicate with coworkers without removing the headphones each time to talk. I would be using my PC as the source. Can anyone recommend a good starting point for each peice of this puzzle? Thanks
jlind325is
Thanks everyone for all the input, this whole idea is boss dependent. He has yet to okay the idea but lets hope he will. Until then thanks, Justin
Justin- did not understand your first post. Thought you wanted to use the Denon as your source. You have it correct. and here are many usb/dacs and some that are usb/dac/hp amp. For a really comprehensive run-down, check out head-fi.org.
Well i got a no go from big boss man. Maybe i will go for a DAC at a later date and use it in the main rig. Thanks anyways guys.