Burp rags, onesies, bottles (if necessary). Also think ahead...We got so much stuff for like the first 6-9 months of our childs life, but when they hit that age/size for clothes, we realized we didnt have much. You'll be having a summer baby so lots of cool clothes, sun screen, hats. Bigger items are always good too, swing, bassinet, car seat, stroller (if you pickedo out the exact one you want), bibs, and socks are crucial too. Even though its summer, they still may need a little something on their feet.
Shoes were the biggest waste until after they turn one. The little Robeez or Target brand leather slipper type shoe is the BEST, the one item I always tell everyone about.
A good diaper bag is important too.
Games for the shower:
Diapers and melted candy bars, guests than have to guess whats inside! Its a hoot to watch people, they can even take a sample on their finger if they like (the candy bar looks like Poop). Very fun!
Gift ideas: $10 gift cards to Starbucks, Caribou, Blockbuster, Barnes & Noble.
Another great idea that should never be bypassed at a shower, as each guest arrives, have them address the evenelopes from the "Thank you" cards you will later send out. Throughout the shower, you can draw envelopes for winners...This also eliminates you having to address each enevelope when its time to write out your Thank you cards.
Most of all enjoy your shower, don't do any work, it's your day to enjoy, so sit back, relax and have fun.