First on the docket is the Black and White flap over laptop case from none other than Tar-szhay. This should fit a 15" PowerBook or smaller (including iBook models). There's a side pocket for your extra geek items, but overall this bag stays nice and sleek.
Next up, the Suva 12" PowerBook Handbag from Willow Design offers a both an outer bag with tons of pockets in a clean bag and an inner removable sleeve for your new lappy. Available in a panapoly of colors, this comfy squishy bag still has a fun shape.
Thirdly, the one-of-a-kind colorful prints on the My Rebe laptop sleeves for iBook or PowerBook are sure to brighten any drab workday (pictured above). They are padded and customizable by choosing a "predominant" color.
Lastly, I'd like to bring your attention to the Brooklyn Industries Laptop Sleeve. These sleeves close on the short edge of the laptop via velcro and come in a collection of hip retro prints.