sdhc to CF adaptor?

[ian in lancs]

I've migrated from a D80 to a D300 so have a stack of 2 and 4GB SD cards. Whats the wisdom on using sdhc to CF adaptors? I have bought 4 4GB CF cards but I'd like to be able to use the SD's as a backup. Also my laptops have SD slots built in which makes for convenient and faster download.