USB FLASH MEMORY
Great For: People with two or more unnetworked computers, or those who ferry files from home to work.
Think Twice If: Your files come from digital devices that require a specific type of memory card.
What to Buy: Sony Microvault ($49 for 16MB to $299 for 128MB), IBM Memory Key ($89 for 32MB), Agat Q ($69 for 16MB to $199 for 64MB).
PERSONAL HARD DRIVES
Great For: Data hogs (think 40GB), such as those who want to carry around their collection of MP3s.
Think Twice If: Size and weight concern you -- they're comparatively bulky.
What to Buy: Archos Technology MiniHD ($199), Apple iPod (at $399, it's not just an MP3 player).
REMOVABLE FLASH MEMORY CARDS
Great For: People with many digital devices that require a specific card.
Think Twice If: You want to share your data with others.
What to Buy: Compact Flash card, Secure Digital card, Memory Stick, SmartMedia card -- many options for all, starting at $18.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.