Despite the recessionary gloom, there’s reason for holiday cheer this year among gadget lovers. Electronics, both home and personal, have become a principal battleground in a fierce price war among retail giants like Wal-Mart, Amazon and Best Buy. With fewer storefronts dedicated exclusively to electronics these days (remember Circuit City?) a lot of market share is up for grabs. Meanwhile, thanks to the Droid, a rash of new e-book readers and price cuts by game console makers, electronics is expected to be a rare bright spot in an otherwise low-key Christmas season for retailers.