I think I've also gone over to the Dark Side.
I recently gave away my ski helmet in favor of a blue one to match my jacket and skis (pants are ALWAYS basic black - like bike shorts or tights).
My mittens and gloves also coordinate.
If it doesn't match directly - it's black.
Sad.
Bike gear not necessarily the same way - my clothes don't all match my bike, but I try to have gloves match the jersey I'm wearing. My helmet (Giro Pneumo) is red/white/blue, which sort of matches my commuter, but not my mtb or road bike. Sigh. I can live with that, however.
It kills me when I would see DH on his rust colored bike (now gone) in a blue helmet and blue LBS kit. Gads! Horrible color clash! He's got to get a new basic silver or ti helmet next!
See...so not only do I try to coordinate myself, I'm trying to coordinate my DH.
It's a disease.
Oh...And I also vote for the blue helmet - if that's your only bike. Go for basic white if you have others you ride.