Jon wrote in post #5644477
Canon says the Large Fine JPEGs on the 40D average around 3.5 MB, so you can get about 2000-2100 on an 8 GB card; around 5200 shots on the cards you have then.
Thanks for working it out Jon.....
tmonatr wrote in post #5644517
Another vote for the laptop. A major plus is you can cull photos as you go.(you can do this in-camera, but laptop screen would be alot better) I would HATE to go thruogh 4,000 pictures when I got back from a trip.
True better for housekeeping along the way, and no editing 4000 pics on return, deffinatly a must get, maybe even on travels as it will be cheaper than dear GB...
anshu wrote in post #5644524
I think the main difference here is raw vs jpeg, but as you say your a jpeg shooter so
4000*4mb=16000mb/1000=16gb. Thats a measly 16gb, so you should be fine with your current setup. If I were you I would at least grab another 4gb just in case. Maybe think about shooting in RAW, its a world of difference!
Yeah, still a JPEG shooter, I believe in one step at a time fully get used to my camera before taking the next step into the RAW world, I've read its loads better and I will get there... give me time 
Thanks for all your help here guys......