Tuneband for iPod Classic 160 GB (OLDER MODEL), Grantwood Technology's Armband, Silicone Skin, and Screen Protector, (Released 09/07)
I've used other armbands to hold my Ipod and this is the best.  It is simple and comfortable (does not pinch like others tend to do) and is comfortable for wearing for long periods of time.  It also easily fits around my upper arm, which others I tried barely did.  In addition it is easy to remove from your arm and the band is easy to remove and replace onto the Ipod skin.