Good speed for a consumer digital SLR.

The Nikon D40's performance is excellent overall. Start-up time is good, and shutter lag at wide angle and telephoto is very good. "Prefocus" times (half-pressing and holding down the shutter button before the final exposure) are quite fast as well, with a shutter delay in that condition of only 0.098 second. Shot-to-shot cycle times are also good at about 0.6 seconds for large/fine JPEGs, and the camera captures frames continuously at this rate. Continuous-mode speed is close to being as stated with noise reduction off, coming it at 2.5 frames per second. With noise reduction on, however, it's quite a bit slower, at about 1.65 frame/second. The flash recycles at about 4.8 seconds after a full-power shot, which is commendable, particularly given the excellent range of the D40's flash. Connected to a computer, download speeds are vert fast as well, so you won't feel a need for a separate card reader. Bottom line, the Nikon D40 is very responsive, good for wiggly kids and most sporting events. Though Continuous mode speed could be a little faster, the camera at least captures frames continuously at that rate, seemingly without any buffer limitation. Great results overall.

Battery
Good battery life with the custom LiIon battery pack.

The Nikon D40 uses a custom rechargeable LiIon battery pack for power, and comes with a charger. Even though runtime is quite good, I strongly recommend picking up a spare battery pack and keeping it freshly charged and on-hand for extended outings. (Digital camera batteries are firm believers in Murphy's Law, always running out of juice just as the best photo ops of the day are available!)

The table above shows the number of shots the camera is capable of (on a fully-charged rechargeable battery), based on CIPA battery-life and/or manufacturer standard test conditions.

(Interested readers can find an English translation of the CIPA DC-002 standards document here. (180K PDF document))

Storage
The Nikon D40 accepts SD/MMC cards, though no card is included with the camera.

We strongly recommend buying a large capacity SD/MMC memory card at least a 512MB card, preferably a 1GB or larger one, to give yourself extra space for extended outings. (Check the shopping link above, cards are really cheap these days, so there's no reason to skimp.)