I love my N900 as my primary device. It's great for full web browsing and the IM/Text features can't be beat. Cisco VPN or OpenVPN is nice in a crunch when I need to admin my servers whilst out and about.

I have unlimited data with T-mobile from an old plan and I can get 5mbps on average here in the DC area. I use qtMobileHotspot to share with other devices. I actually carry an iPhone with no SIM for Apps and tether to N900. I find the combination of iOS device and my N900 to be the best of both worlds.

N900 is my utlra-mobile computer and the iPhone is for Apps when I need them. Works well for me.