I just converted last weekend from a windows based laptop to a iMac, too be honest it's an amazing piece of kit. Yes you can have a problem because everyone else is running windows, but you can get software for that the mac.
Apple certainly know how to produce a product that catches people imagination. They say the ipad is going to have 3g, so some sort of connect to a network will be required. It certainly looks the biz, but can't see me shelling out £500 for one when I already have an iPhone which has good Internet access as it stands.