That means you need to keep the iPad close enough to tap on its screen for those functions that the wireless keyboard doesn't support. If you want the iPad screen to be at a more monitor-like height when using the wireless keyboard, and still keep the Apple iPad case on, consider getting Griffin Technology's $30 Loop for iPad stand.
Keep in mind that the Apple wireless keyboard is very thin and light, so it could easily travel with you. An iPad, keyboard, and 10-watt power supply together weigh less than 3 pounds -- less than half the weight of a laptop and its power supply -- and the iPad items together take less room as well.
Mice. The iPad's touchscreen is sensitive enough for navigating the device and even moving the text cursor in your documents, thanks to aids such as the magnifying glass that appears when you are moving the text cursor. But a mouse would be a better input mechanism for graphical tasks, from flowcharting to photo retouching. And a mouse would be better when using thin client and cloud apps whose UIs assume a mouse. A touch UI is great, but touchscreens' sensitivity is not yet as fine as a mouse's.
Unfortunately, you can't use a USB or Bluetooth mouse with an iPad. Enabling Bluetooth mice would make the iPad much closer to being a laptop replacement -- which is perhaps what Apple fears, even though a fully loaded iPad costs almost the same ($830) as an entry-level MacBook ($999).
Printing. Then there's output. A common output need is printing. Fortunately, several iPad/iPhone apps allow printing via Wi-Fi to wirelessly enabled printers. Of course, both the iPad and printer have to be on the same wireless network. Even more apps use your Mac or PC as a print server, but that means being near the desktop computer or the Wi-Fi network it's on when you want to print, which won't help you elsewhere, such as at client offices. The iPad really needs a native printing facility (which Apple CEO Steve Jobs hinted was coming, in response to a question at the recent Worldwide Developers Conference).
Display. Many tasks need far more working room than the iPad's screen provides, especially given that the virtual keyboard takes nearly half of the screen space when the device is in landscape mode (as it is when using the Apple iPad case as a keyboard tray). For a larger display, you can connect the iPad to an external monitor, projector, or VGA-equipped TV screen using Apple's pricey, $30 iPad VGA connector cable -- and you get more pixels, the full 1024 by 768 pixels of a typical 17-inch monitor.
But -- and this is huge -- it works only with a handful of iPad apps: the $10 iWork Keynote, the built-in Photos (and only when displaying a slideshow), the built-in YouTube app (as well as when watching YouTube videos in the Safari browser), and the built-in Videos app. So you can't use it to do email, browsing, or other work you'd want to view on a larger monitor. That's nuts. Imagine the Apple engineering hours spent to have the iPad turn video-out on and off based on what application is running. Another sign of Apple's possible fear that the iPad could threaten laptop sales.
I fantasize about a future in which monitors are Wi-Fi-enabled (as some projectors and TVs already are), so I can connect the iPad to one without a cable -- assuming Apple stops blocking the video-out signal from most apps, of course.
We Need a Docking Station. The bottom line is that you can use only one wired peripheral at a time with an iPad, and just a handful of wireless ones.
There are no hubs that let you plug in multiple devices for simultaneous use by the iPad -- as we're all used to with USB peripherals. That means you'll likely be plugging and unplugging various devices from the iPad -- the VGA connector when you want to show a keynote presentation on a projector or watch a video or slideshow on a TV screen, the keyboard dock when you want to do a lot of typing, the Camera Connection kit when you want to transfer photos, the sync cable when you want to sync your iPad to your computer, or the power adapter when you want recharge the iPad. Even if you use a Bluetooth keyboard, you'll still be switching among multiple wired devices.