Hey dub Beatz,
I have the HE-300 and love' em. I have plugged them into various amps and they do not disappoint. Was listening to them today from an iBasso P3 while rolling op-amps with an iPod touch (line-out). Great sound.
Now, I'm a dac and source guy myself, so I would recommend at least an inexpensive one to get you going to bypass onboard sound. But that's just me.
I would get the HE-300 from Amazon and maybe E07k ($89.00) or maybe the new E10k ($75.99) that just came out (I have the E07k, have not listened to the E10k though).
Just throwing out other options for ya.
I have the velour pads on the HE-300. Did not like the pleather pads. Sound is too dark and congested with 'em.
Cheers!
Great advice here!
Using a DAC is hardly about just eliminating noise; though it certainly should do that. Getting even an entry level DAC, compared to your onboard sound, will noticeably improve overall clarity and soundstage. To use the common analogy, it'll be like removing a veil from the sound. Then again, if you don't get a DAC, you won't know what you're missing Ignorance can be bliss.