Hi i have just purchased a Nikon D5000 and am wondering what the best memory card would be for me in terms of all round good performance and writing speeds, i am looking at either the 8gb or 16gb in either the SD or SDHC any help would be fantastic.
If you are going to be shooting fast moving action, I would suggest SanDisk Extreme series cards or at least the Ultra II series, also from SanDisk. Ultra II series is older though and may be hard to find. The camera's built in writing speed will be the limit of how fast the images are transferred to the card and from what I have read, the D5000 has very good transfer speed. Here is a link
to dpreview.com's review of the D5000.
If, however, you are mainly shooting landscapes, macros or portraits then I would suggest "regular" SD cards.
I have an older D-SLR and have been using SanDisk Ultra II CF cards and haven't had a problem with any of them.