sharing contacts across two appleIDs

I've just purchased a MacBook Air for my wife: her first apple "computer" ever. She has an iPhone and we share an iPad. I've long used MacBook Pros.

tonight we're gonna get her set up. I'd REALLY like for her to have her completely OWN system based on her own Apple ID, BUT there are a few things that make us wonder if that's a good call. The bottom line is that we'd like to share our contacts, and our music (and perhaps our app purchases, tho that's not a killer for us.)

Can we share contacts yet across multiple Apple IDs? Any chance it's coming soon?

Tho it may be too late by the time you read this, any thoughts on using MY Apple ID with the new Air, versus using hers? Each has benefits and limitations, as I see it. thoughts?