hello guys! I'm quite new here, and new to the whole audiophile territory, but I have been doing my research since a few days, and I think I've arrived to the point when I need your help.
so, I'd like to know what would be the best upgrade if I have.. let's say $150-200 to spend.
 
my current "setup" looks like this: FLAC > M-audio audiophile 24/96 > ancient sony hi-fi set (doesn't worth anything now) > Grado SR125i
so it's really basic and doesn't even qualifies as a setup. but I think these phones are more capable than this.
 
since the Grados are very easy to drive I guess I'd rather need a DAC than an amp..
however, I've read in the hydrogenaudio forums, that..
"The DACs on the Audiophile 2496 are of very good quality. You will not get any noticeable improvement by using an external DAC. An external DAC would not put you one bit ahead unless it also contained a headphone amplifier, otherwise trying to use it would be exactly the same as trying to connect the headphones directly to the card."
..reading the forums here I'm not really sure I can trust this.
so this would be my first question. can I trust this, and simply buy an amplifier (little dot series tube amplifier maybe) or second:
buy a USB DAC, without a separate amplifier (since the Grados are easy to drive)?
 
I did a "little" investigation and narrowed down my choices to four, but rather two models: the Nuforce uDAC and the HiFiMAN HF2. (the other two were the Maverick Audio D1 and the Zero DAC/amp) 
the HF2, unlike the others, is a tube DAC/amp, in which I'm also really interested.
.and today I came across the Little Dot DAC-I, so I'm adding this to the poll as well, because I haven't read any negative opinions about it. (little out of my price range, but looks like a really good deal)

please help me to decide, thanks!