I don't consider my netbook a full blown laptop replacement
I purchased a Dell Mini 9 early after they were introduced. I tweaked it with 2GB of RAM and a 32GB SSD and a larger battery.
I've tried Unbuntu on it and I'm currently running Windows 7. I most certainly don't consider it a laptop replacement compared to my MBP. What I really wanted the Dell Mini 9 for was e-mail, and Internet access. I also streamed music through it. For me it has been basically a device I take to a coffee shop or on vacation or business trips when I want to keep on top of things at work.
For the things I want to do with a netbook the iPad would certainly handle those limited tasks. So for me the iPad is going to replace the Dell Mini 9.
The 3G plan on the iPad is something that i've wanted for a long time on my laptops, but he price of $60.00 with a contract kept me away from that. The iPad's no contract plan, and $30.00 a month seems like an incredible deal to me.
I don't think I have been doing a lot of multi-tasking on the netbook. So event though I'd like to see that in an iPad I think I could live without it without much fuss. I just wish I could stream music and surf at the same time.
Gaming? Well as an iPhone user the small screen just didn't work for me. However on the iPad I think I may finally have some fun
If I wanted the best of both worlds I think a MacBook Air would probably be the best compromise if I wanted a small, thin, light, laptop. If they offered 3G on the next one at the price of the iPad that just might make me rethink the iPad.