Incipio's Orion ($20) is your basic sleeve/pouch case, designed to keep your iPhone safe in transit, but to be removed when you use the iPhone. The Orion is made from a leather-like material stitched together on three sides to form a pocket with an open top, and it includes a soft, micro-suede liner on the interior. There's no additional padding, though the case is reasonably thick. It's available in any of eight colors--white, green, pink, brown (Zune envy?), burnt orange, blue, black, and camouflage--so you should be able to find one that matches your personal preferences.
The Orion also features Incipio's unique EasyReach system, which makes getting your iPhone out of the tight-fitting case quite simple. EasyReach is a strap that's secured to the inside bottom-front of the case but lays against the inside back of the case. When you push your iPhone down into the Orion, the phone pushes down on the EasyReach strap, pulling it into the case, where it winds up nearly flush with the case's top edge. When it's time to take the iPhone out, a quick pull on the strap pulls the phone out about an inch, from which point it's quite easy to pull out with your fingers. (There's a cutout in the back of the case, so you can easily grab the strap. In the photo at left, you can see the top of the strap extending beyond the case.) If you receive a call when the phone is in the case, the EasyReach strap makes it simple to get to the phone quickly. Apple's Leather Case for iPods offers a similar pull-strap system, but costs $99, thanks to real leather and an internal support structure to strengthen the case.
About the only issue I had with this case is that it definitely affects the volume of the iPhone's ring. If you've chosen a quieter ring, and/or you keep your volume low, you may find that the case makes it difficult to hear when your phone rings--there's no cutout for the speaker, and the case and liner do a fairly effective job of muffling the iPhone's sound.
If you're looking for a relatively inexpensive carrying case that offers good protection for your iPhone's screen and other scratchable parts, the Orion is worth a look.