While I think the input from others is correct, I too am guilty of making fun of my friend's registries and all their excessive useless stuff.
Currently I am registered for about $300 worth of cloth diapers and accessories at kellyscloset.com
I already purchased the infant carseat.
I made my own moby wrap for only $25 (for enough fabric for 2!)
I made cloth wipes from old clothes.
My inlaws want to buy the crib.
My friend might be giving me her bouncer and travel swing (I wouldn't get a swing otherwise)
When I register I will be asking for:
Convertible carseat (trying to think of things I will need when they are older)
Potty chair (will be attempting elimination communication)
Possibly a travel booster chair of some sort for grandma's
Bumbo with tray
No bottles, but maybe sippy cups and baby dishes for when they start solids
Crib mattress protector
Pack & Play
Umbrella stroller (I think those big bulky ones don't get used enough)
I might include some baby towels, bibs, blankets, and clothes, but I know people just buy you that stuff anyway. We won't know the gender so some people might not know what to get.