How I used to pronounce some Pokemon names:
Omanyte/Omastar: OHM-ah-night/star
Croconaw: KRA-kuh-naw
Xatu: EX-ah-too
Marill: ma-RILL
Azumarill: I used to say the "marill" part just like the Pokemon Marill. Instead it's prounced like how I first thought Marill was pronounced.
Misdreavus: mis-DREE-vus
Wobbuffet: wah-BUFF-et
Houndour: houn-DOOR
Elekid: ELL-uh-kid
Raikou: rye-KOO
Entei: EN-tie (like "hentai" without the H)
Suicune: SOO-ih-koon (just like suicide!)
Pupitar: POOP-ih-tar
Celebi: sel-LEB-ee
Sceptile: SKEP-tie-ull
Poochyena: pooch-eye-EE-na (as if it had "hyena" at the end)
Gardevoir: GAR-de-vor (I was obviously unfamiliar with French)
Plusle: PLUS-lee
Manectric: ma-NECK-trick
Volbeat: VOLE-beat
Trapinch: TRAP-inch
Milotic: like "melodic"
Banette: ban-NET
Bagon: BAG-on
Groudon: GROW-don
Rayquaza: ray-KWA-za
Bonsly: BON-sly (as in the word "sly")
Uxie: OOK-see
Names I stubbornly pronounce wrong:
Illumise: ILL-oo-mise ("Ill-oo-MEE-zay"?! What the heck?)
Vibrava: vai-BRA-va
Bidoof: bih-DOOF
Arceus: are-SAY-us
More pronunciation notes:
Pidgeot: Apparently the Pokerap used to say something like "PID-jit", so that's how I pronounced it until I saw Pidgeot in the anime...
Machoke: I still hear many people put the accent on the CHOKE instead of the MA...
Finneon: My friend pronounces it "FIN-yun"...
Dialga: A lot of people pronounce it "dee-AL-ga", whereas I pronounce it "die-ALL-ga".
Giratina: My friend pronounces it "jer-AT-in-uh"
Manaphy: I hear quite a few people saying "MAN-uh-fee", as in the word "man". I pronounce it just like the Japanese name.
Names I'm still unsure how to pronounce:
Bibarel: I currently pronounce it bih-BEAR-uhl (the last part is like "barrel"), but still that seems wrong...
Vespiquen: I always pronounce it "VES-pih-queen", but why, then, isn't the name spelt "Vespiqueen"?
Mismagius: "Mis-MAGE-ee-us" makes the most sense to me, but I'm not sure about it... (It would be a shame to mispronounce my favourite Pokemon!)