Any tips for clear/sharp thumbs ?

[SeeNudity]

I look at a lot of the TGPs and galleries out there and see some people creating incredibly high quality thumbs. They are so clear and sharp, and mine don't typically touch that quality. I've been testing some of the sharpening filters and unsharp mask filters which seem to help. I typically crop my pics when making thumbs to try to remove some of the dead space or to draw attention to the focal point of the image.
Anyone have any recommendations on achieving high quality thumbs while still minimizing file sizes? I have ImageReady and Photoshop7 but am not opposed to looking at/using another product. Any tips or recommendations appreciated.