I have the 4gb Asus eeepc which I just took on a 5 week road-trip round the USA with me - it was perfect! Really good for the price (I had it on order for aaaaaages, but it was sold out everywhere, and I actually ended up buying it at Heathrow airport for cheaper then I had seen it everywhere else!)
Ultra portable, very useful! The keys are pretty small, so not too great for long IMing, but otherwise brilliant!
I would recommend it, but I've also heard great things about the itouch!