Well for a case, I bought my case at the Apple story. BestBuy also sells cases along with a bunch of other stores, but I prefer getting those straight from Apple. My case I got (Speck Candyshell) came with a screen shield. To be honest... I think screen shields are pointless. Sure I guess it's a little extra protection, but I also have an iPod Touch along with my iPhone, and I've never put a screen shield on it, and I've put that thing through hell. I don't even have one single scratch on it. The glass is very hard to scratch. A case is a must though. I'd say get a nice and protective one, even if it adds a bit of bulk. My buddy use to also say "How the hell can you use that case" (Since the speck case does add a bit of bulk) But two weeks later, he drops his phone on a tile floor... Good bye iPhone. He no longer has one. So make sure you get a nice and protective one. The case is to protect your phone, and not look good. Which most people don't understand until they lose their phone.
I bought an iPhone Car/Wall charger (It's both in one) for $15. I thought it was a great deal. It's very useful, and great for trips! I bought that at bestbuy. For the holder, I'm not too sure. Maybe search it online, and see which stores have one.