My tops would have to be (in no order)

Harry Conklin (Colorado's own Jag Panzer)
Matt Barlow (former Iced Earth)
Matt Aub (Timelord/Forgotten Realm)
Ronnie James Dio(Yes, he is American and I would say He's a power metal singer)
Geoff Tate
Tim Owens (former Priest/current Iced Earth)
Corey Brown (Magnitude 9, Redemption, Balance of Power, and colorado's own Section 16)
Michael Lance (Ancient Cross, out of Texas)
Jon Oliva (Savatage)

The late great Carl Albert (R.I.P.) from Vicious Rumors was absolutely amazing. Carl was technicaly as good as Geoff Tate but with the "ballsiness" of Dio. Most of Vicous Rumors' early/mid 90s albums with Carl are very hard to find in the USA. I have two of VR's out-of-print albums on CD. (Vicious Rumors and Welcome to the Ball.) I will gladly send a copy of the aforementioned discs to anyone that is interested. Carl Albert was one-of-a-kind...a masterful American heavy-metal vocalist.

I'm voting for R.J. Dio!

SteveWrote:
I'm voting for R.J. Dio!

i would too!

Here are some other kick-ass American "Power-Metal" vocalists:

John Cyriis- Agent Steel (*One of my all-time favorites!)
Steve Plocica- Apocrypha (*An absolutely KILLER voice.)
Rob Rock- Driver, Impelliterri, Avantasia (*Rob is a VERY under-rated singer)
Sean Peck- Cage (*Slightly "untamed" but very cool nevertheless)

I agree with you on Sean Peck. Still one of the rare singers with a diverse style. Some other favourites:

Matt Barlow - Still my all time favourite. Emotion, power and brutality. A powermetal singer who also gives the low tones a go.
Warrel Dane - Amazing on the Sanctuary-stuff, a shame he doesn't sing that high-pitched anymore. Nonetheless I'm also quite fond of his lower, dramatic style of singing.
John Cyriis - Alien.
David DeFeis - Unique and touching.
Mark Shelton - Really keen on the rasping kind of vocals.
John Arch - Love his melodies.

This is going to be a long list. Well, some other names: Tim Aymar (on that Control Denied album), James Rivera, Alan Techio, Midnight, Harry Conklin, etc.

Steve Plocica is one VERY HELLISH vocalist and METALLORE would like to get in touch with him on MySpace@jjloozer or e-mail jjloozer@yahoo.com.