In my opinion its all very personal. When you see a song that is out of your reach, all you need is determination and perseverance. Just say too yourself "Man that's fucking hard, I wanna play that" and over time youll learn the tab (since going at it straight might put you off)

To contradict myself, Psycroptic songs get you to that "higher level" (unless you blast Necrophagist all day, which most of us dont, so it is worth a mention)
Psycroptic = heaps of tremolo picking, nice doomy riffs, catchy, and awesome.. give it a shot!