right, so my shiny new K10D says it takes SD or SDHC cards

however, nowhere in the instructions does it give any advice on cards.

For example, I have seen SDHC cards that say "Class 2", "Class 4" even "Class 6" on them. - do these classes make a marked difference to anything, other than the price ? And is it worth paying for the label ?

for example, 7dayshop have

SDHC 4Gb, Class 2, from Sandisk, at 14.99

SDHC 4Gb, class 4, from Kingston at 15.99

and is it worth having SDHC instead of SD? my laptop (3 yrs old) has an SD slot, but I'm guessing it won't read SDHC through it.

and with SD cards, is it worth paying a lot more for the ones that say they are a lot faster ? is it false economy to pay just £6 for an unbranded 2Gb SD card from 7dayshop, when they also do:

Sandisk "normal" 2Gb - £8

Sandisk Ultra II 2Gb - £13

Sandisk Extreme III 2Gb £17

all advice gratefully received.

Speed Class Ratings specify the minimum sustained write speed to an empty SDHC:

Class 2 = 2 MB/s

Class 4 = 4 MB/s

Class 6 = 6 MB/s

SD products can't use SDHC memory addressing so won't be compatible unless specifically stated. So you may need a separate reader, or read via camera cable in your laptop.

Write speed is also limited by the camera hardware, but generally a faster card means you wait less time between taking photos - whether that's a benefit depends on your shooting methods/style.