it was discussed before, both sd/cf and backpack - please do a forum search.

As sevencrossing indicates you will end up with several regardless of how carefully you choose. I have a d800 and d7000 and carry 2-3 lenses (usually one on each body and a 14-24mm), I started with a shoulder bag (think tank retrospective 30) which has a nice unassuming casual appearance, I still like this bag because of the enormous amount of room it has (the two front pockets can hold a dslr and sometimes a dslr with lens mounted, I usually leave those pockets empty for handy places to change lenses). I found though it is a bit uncomfortable for heavy loads and long sessions. Also, it tends to change shape as you take large things out (the place you had your dslr tends to just close up as the rest of the items in the bag move together naturally...there is no hard shell support to hold the bag shape).

I then bought a think tank sling bag (I think it is the sling o matic and was the largest size). This is much more comfortable and wears like a back pack. It is large enough to have a d800 with 70-200 horizontally with room underneath for mutiple other lenses etc. I have the d800/d7000 with lenses mounted face down side by side and the 14-24 next to those, there is even room for flash and two other small lenses. This bag allows you to quickly sling the bag in front of you giving you easy access to your gear without taking the bag off, it also maintains its shape well. It has room for a small laptop and you can strap a tripod on the bottom. The compromise over the retrospective 30 shoulder bag is that it doesn't have extra floppy loose outside pockets (everything must fit in the rectangular shape of the bag).

If you are set on a backpack I would suggest you go to Thom Hogan's website and click on the nikon tab at the top. You will find a link in the large number of reviews and essays on bags/backpacks where he gives an exhaustive discussion of what he uses and why (he uses backpacks).

Finally if at all possible visit a camera store that has multiple brands and models on hand. If you buy online you are guaranteed to be buying a lot of bags before finding exactly what you want, there are so many subtle aspects to every design and whether or not it really is a good fit might not be apparent until you start loading your gear inside.

If I was going to hike and go camping I'm not sure how I would go about it (maybe put one of my loaded bags into a large camping backpack with the camping neccessites? I would still want something to carry my gear when I got to my location.

What I personally like about both of my bags is how quickly I can deploy and handle my gear and how quickly I can stash it all again (all without taking the bag off).

jptalledo said:

What about choosing between compact flash or SD card? any suggestions?

thanks

you want at least one of each

http://nikonrumors.com/forum/topic.php?id=89&page=5

Bags are like lenses, you can't have enough of them ( I had 6 at the last count )

Can anybody suggest me a good bagpack for D800 and 2 extra lenses?

What about choosing between compact flash or SD card? any suggestions?

thanks