Pokemon XD: Gale of Darkness

Get 10 Master Balls (Without Multplication Trick)
Once you defeat Naps, return to where he was standing and you will suddenly go down to a Lab and find a Master Ball. There will be a Chansey in the Master Ball, holding Lucky Punch. When you pick the ball up, a door will appear. Enter and you will find 10 Master Balls on a desk.Take them and now save your game.
(Thanks to Yankee1c@aol.com)

Get the Three Johto Starters
Beat 100 trainer Mt. Battle Challenge for each Starter; Chikorita with Frenzy Plant, Cyndaquil with Blast Burn and Totodile with Hydro Cannon.
(Thanks to billis_2k@hotmail.com)

Item Choices
In the interview with Acri in Gateon Port, you can get these items by answering as follows:
Amulet Coin: Say "Yes" to every question.
Mental Herb: Say "Yes to 1 question.
Quick Claw: Say "No" to every question.
White Herb: Say "Yes" to 2 questions.
(Thanks to gonzalec@verizon.net)

Purify Lugia
Lugia can be caught at Nickle Dark Island. He comes out at Level 50 after you defeat chiper boss, Deathgold. To purify Lugia, get full Tempo in all 9 chambers, then place Lugia in one of the sets.
(Thanks to liam martin)