I just tried all my 4GB cards and all worked:

Transcend 150x
Ridata 150x
PQI 150x

is it best to go for SD or MMC?

any tips for UK place to buy online?

I'd go with SD for the larger capacities and lower prices, but stear clear of SDHC / SD 2.0 cards - chatting on #maemo the opinion is definately that SDHC / SD 2.0 cards won't work as there is no kernel support.

Online in the UK you can try the following (I'm not recommending these firms btw, as I've only ever used Expansys myself in the past)

Moby Memory
My Memory
Expansys

cheers - I've used moby before and it was very quicka nd seemed a good price - I'd thought MMC were meant to be the cheaper, will check out!

Yes, I can confirm that an 8 GB SDHC 2.0 card will not work. I borrowed an AData 8 GB and it is not recognized by my N800.

I'm currently using dual 4 GB Patriot Extreme SD cards:

http://www.newegg.com/Product/Produc...82E16820220146

Has anyone done comparative N800 testing on SD cards with different speed ratings? In other words, is the transfer rate bus bound or media bound? I'd personally spend more for faster cards *IF* they provide a real benefit, but not if the channel saturates before the card tops out.

any more info on this topic?

having done a little research into it there doesn't seem to be much difference between SD and MMC to me, is it just a case of getting the best price on a brace of 4gig-ers? MMC seems less expensive option...

I believe the pinout on the SD & MMC are very similar if not the same, but the MMC is a bit thinner, which make it harder to get as much storage as SD.

I don't think the thickness means much one way or the other, some SDs are as thin - I have one thin 512MB SD card and one thin 1GB SD card, amongst the other "normal" cards.
The biggest difference between MMC and SD is that MMC uses 1-bit transfers (i.e. it has 1 connector to transfer data) while SD has 4. But SD can also work in MMC (1-bit) mode (which has slower maximum transfer speed, obviously), and some SD controllers on some PDAs only uses 1-bit mode as well.
Now, MMC plus has extended to 8-bit mode, if I remember the article I read on wikipedia correctly.. certainly the one card I own is _stuffed_ with connector leads!

Don't know if it works with the N800, but buy.com currently has a Kingston 2GB SD card for $9.95 after rebate (from Kingston). Sku is 202743332