Definitely try
Blind Guardian,
Helloween,
Gamma Ray and
Stratovarius; they are some of the forerunners of
Power metal.
Edguy and
Avantasia both feature lead vocalist Tobias Sammet, and both bands have some great releases. One that was just made recently is Royal Jester. They released their debut with the same name in 2010, great, solid
Power metal.
Symfonia is also very good; their album In Paradisum is just a great
Power Metal record and features guys from
Stratovarius,
Angra and
Sonata Arctica (which are also great
Power Metal bands). Borealis from Canada is also phenomenal, great fun to listen to. Others I really enjoy are
Power Quest,
Pagan's Mind,
Masterplan,
Shaman, Sinbreed and
Savage Circus. If you are looking for something more folk as well, I recommend
Alestorm, which is pirate themed, and
Stormwarrior, more
Viking Power metal. Hope this helps!