Bass
Sean Beasly (Dying Fetus)- Amazing bassist, technical as crap, he can keep up with John Gallagher on his bass, 'nuff said.
Orion (Behemoth)- Not the most technical bassist, but he definately stands out for sure as he makes sure he's known, also he's a really nice and humble person despite my views on Behemoth's ideas.
Alex Webster (Cannibal Corpse)- Also very technical, he uses a 5 string bass, which I also think is really cool. More and more metal bands are starting to use those as well. He is actually the person who inspired me to play bass. I actually have plans to give him a B.C. Rich Warlock bass if I ever meet him in person.
Jonas Bjorler (At the Gates)- Amazing bassist as well, as would anyone who plays with At the Gates.

Extreme Vocals
Nergal (Behemoth)- He does his vocals using a different growling technique but it's brutal as all hell. Listen to At the Left Hand ov God and tell me that ain't powerful.
David Vincent (Morbid Angel)- A lot of fans tend to ride his nuts when it comes to his vocals on Altars of Madness, but me personally I like his guttural roaring on Domination best.
Johan Hegg (Amon Amarth)- Powerful vocalist and has the best roaring in modern Swedish Death Metal.
Chris Barnes (Cannibal Corpse)- What a shame how his growling is piss-weak nowadays, because back in 1991-1994 he was literally the the most guttural vocalist around. On Tomb of the Mutilated his vocals were so inhumanly low that on the back of the cd cover they had to write "No harmonizers were used to create any vocals on this album"
Trevor Strnad (The Black Dahlia Murder)- He has a great vocal variety and cool rhythms, his low growling isn't the best, but it fits with his music. His high pitched melodeath screming, on the other hand, is friggin awesome, and, unlike most modern day screamers, they have power behind them. Most of the modern day screamers sound like they've had their testicles removed (aka Oli Sykes)
Antti Haapanen (Noumena)- Extremely powerful Finnish melodeath vocalist, and surprisingly guttural. He almost rivals Johan Hegg.

Piano
Beethoven- Do I even need to explain??? Moonlight Sonata is one of my favorites
Mozart- He is intricate as well as smooth and relaxing as well
Strauss- I'm not too familiar with his work but I've heard a couple of his songs and I have to say they stood out for sure.

Guitar
Karl Sanders(Nile) - His playing Sucks sometimes but what the hell! He's a genius on the songwriting side. His solo project also inspired me to do a solo project too.
Chuck Schuldiner (Death) - His sound made me realize the meaning of "Trendy". Unlike most of death metal bands these days, He is naturally Brutal without the use of GORE.
Mikael Akerfeldt(Opeth) - Versatile, He has actually the Largest percentage of influence in my Style of Playing today.
Shawn Lane - Almost same as Mikael, He Baptized me with very Touching/Melancholic/Nostalgic Guitar Lines.
Allan Holdsworth - He has The Strangest Chords ever, So weird but still Catchy and Listenable.
Jason Truby (ex-P.O.D., Living Sacrifice) - He's the reason why I listen to P.O.D. (the only NU metal band i dig). He's the Best guitarist that has played Nu Metal. he also has an acoustic Solo project which contains my favorite tunes.
Brett Garsed(Solo, Ex-Planet X) - Very Melodic tunes, my influence in using Chromaticism.
Stephan Forte (Adagio) - One of the Few Neo-Classical Guitarists that I dig, also I admire the mixing of Classical tunes with Death Metal-ish riffs.

Vocals
Mikael Akerfeldt (Opeth)- Versatile. He can do the Total Opposites of Vocal styles.