Well, I am not into full blown Death Metal like Cannibal Corpse. I listen to them occasionally just if I need to listen to something heavy but I prefer melo-death, which is totally different. Melo-Death is much MUCH more technical and as the name suggests focuses on the melodies. Children of Bodom aren't Melo-Death, I'd say Melo-Black metal, but if you listen to their old stuff (listen to a song called Kissing the Shadows or Black Widow), you can definitely tell what I mean when I say melodic.
Judas Priest and Maiden are among my favorite bands, Glenn Tipton is awesome!
I am teaching myself to properly shred now and it is tough. I get super impatient playing so slowly so I often only practice for like 5-10 minutes at a time which isn't enough.
I don't know how to sweep pick yet, but I am learning and my suggestion would be to learn easy sweeps (like I am learning), then once you can play the easy ones, try harder ones, and then try the stuff from Jari Maenpaa (check his stuff out).
You may not like Children of Bodom but I suggest learning the song "Towards Dead End" which I am learning, as it has some easy sweeps (19-18-17h22p17-18-19 on the G B E strings respectively, as well as a tougher one, 14-15-12h17p12-15-12). I think if I can play these to speed that I'll get the rythem down to learn some harder stuff, which includes 4 strings, then 5 strings. My goal for the year is to learn the entire Hatebreeder album, and all it is is shredding. haha I can play most of the rhythms but no solos yet.
Also, for those wondering, I am trying to sing over "Holy Wars...Punishment is Due". I can almost do Holy Wars, but the Punishment is Due part is so freakin' hard to play and sing at the same time. I can almost do Headcrusher, except for the bridge part.