DO NOT, I repeat, DO NOT register for ANY BABY CLOTHES. For any reason. Does nobody remember how many baby clothes you get at a baby shower??? Especially 0-3 month sizes? No no no... whatever you do, do not register for baby clothes, baby hats, baby socks, or receiving blankets. You will be drowning in them, no matter what, and you don't need to encourage the flood to be any bigger than it must be.
We kept our Target registry quite small, so that when people got there and saw that we didn't have much on the registry, they just bought us gift cards, which we could then use to buy groceries later.

This worked out beautifully for us.
Good things at Target to register for:
- breast pump
- breast milk storage bags, milk cooler bag, glass or BPA-free plastic bottles and lots of #1 nipples (if she's going to be nursing and pumping, she'll want to use the newborn size bottle nipples for a long time, so she'll want extras).
- BumGenius or FuzziBunz diapers (register for 24-30 diapers)
- nursing tanks (they really are great there)
- did I mention NO BABY CLOTHES??? Or socks??? A couple of pairs of the Target brand Robeez knockoffs are probably a good idea, though.
- California Baby diaper cream, baby wash, etc. Or Burt's Bees, I guess. They have other more natural kinds of baby creams, too.
- a big swaddling blanket if they carry them (do they have the Miracle Blanket in their online store?)
- a baby scale is sort of a fun thing to have - we really like ours, even if it doesn't get much use
- definitely a good digital monitor (Graco makes a really excellent one)
- toddler stuff: bibs, spoons, sippie cups, teethers, etc.
Good luck!!!