Wirelessly posted (Mozilla/5.0 (iPhone; U; CPU iPhone OS 4_1 like Mac OS X; en-us) AppleWebKit/532.9 (KHTML, like Gecko) Version/4.0.5 Mobile/8B117 Safari/6531.22.7)
As much as I love my iPhone, it is NOT drop friendly out of the box. Get a good impact resistant case that has a raised rim around the front glass. Bumpers are better than nothing, but I'd go with something like an Incipio NGP or maybe even an OtterBox.
The NGP fits beautifully, is made from a hard rubber, (absorbs impact and provides grip) and gives about 1/8" lift around the edges of the front glass. (back is completely covered) Button presses are as easy and positive as I've ever seen in a one-piece case. Available in a variety of colors including transparent smoke and cost around $20-$30 in the States. My only gripe is that they tend to lift up the edges of screen protectors slightly.
OtterBox has even more protection but you tend to either love it or hate it, and it costs twice as much.
Sean