Sold in two versions -- one for the third-generation iPod nano ($30), and one for both the iPod classic and iPod touch ($30) -- Case Logic's new True Sport Armband isn't a radical departure from others we've seen, but has a few unique details. There's the front face, which has a matte finished screen protector rather than a glossy one, a pocket for cash or keys, and the rear, which has padded bumps to help stabilize the iPod on your arm without exposing…