I'm 33 weeks and had my shower last Saturday afternoon. We opted for a couples shower with loads of food and drink (alcoholic and not - we don't drink, but many of our relatives do and I think the men appreciated being able to have a beer!)
We invited about 45 people (friends & family), and ~35 came (the others were either sick or are currently out of the province or country). It was a bit of a madhouse with 35 people in our 3-bedroom apartment, but we had a ball. There were people aged 25-85 all hanging around together playing silly games and talking, it was a terrific party. My two best girlfriends organized the entire thing, my husband greeted people at the door and took coats, and everyone mingled and ate until they nearly burst.
I highly recommend registering. We tried, but the store's registry machine has been broken for the past six weeks so everyone resorted to getting whatever they felt like. We ended up with WAY too many clothes and still need to buy quite a few essentials, but the shower gifts definitely put a dent in what we need to purchase for ourselves.