Pros:
Seriously easy to travel with.
Fast UI and overall performance.
Amazing battery life (legit 10+ hours)
Fun to use.
Crazy app selection with thousands of iPad specific apps.
Easy to find accessories.
Super well built.
Cons:
No flash, although I don't miss it very often. Skyfire browser will play flash videos.
No external memory slot (big deal to some)
No camera for video calls (on 1st gen)
I wouldn't consider this as a laptop replacement, but more of a laptop's little buddy. Perfect for web browsing, watching video either native or Netflix/Hulu and apps/games. You can get work done as it supports Office suite. If I were to carry around just one thing and I used it for work it would be an 11.6" Macbook Air. I know that other things are more powerful and cheaper, but I don't care that thing is sweet.
My iPad lays next to my chair and I always reach for it instead of my laptop first.
I love it for what it is because it does that very well. It's not just a big iPod Touch. There are so many apps made specifically for the iPad or enhanced for it that it makes a big difference. Apps like Pages and Amplitube are just amazing to me. I don't think you can go wrong with one as long as you know what you want it for and it suits your needs.
There are a ton of tablets on the way, but I don't think that the mainstream models such as the Xoom and the Playbook are going to make a huge dent in iPad sales. There just something about it that just works and is very fluid. I love Android, but anyone who says it's fluid is in denial. HP/Palm should be showing some exciting stuff tomorrow at their event so keep an eye out for a WebOS tablet.