my gf hates the xbox controls (do NOT let a loved one play Portal with you...they will hate you in 5 mins)....anyway....she couldn't get used to the joystick operation for the 360 so most of our LEGO games are on the Wii, just cuz the simple movements are easier. However, if you want better graphics (yes even in LEGO games), the XBOX/PS3 is the best by far. You'd think cuz it's LEGO it doesn't matter but LEGO Harry Potter on Wii with the really dark water levels was near impossible to play, where as the PS3/360 version looked almost 3D.
$50 on xbox $40 on Wii
Just ask if the $10 is worth better graphics orrrrr do you want to save a few bucks and go with a debatably easier control settup.