The AirTel GPRS (EDGE) service on my iPhone that I wrote about earlier is working well but a little slow. Something like 60 Kbit/s down and 40 Kbit/s up at best. For Twitter and some e-mail on the iPhone it’s ok but when connecting a MacBook via tethering it’s to slow.
After having enough RAM, extending your screen real estate is probably the best productivity enhancement you can do. Apple has supported dual displays on Macs since the late 1980s and nowadays even Windows can do it. I have used dual displays with some of my older setups but that was some time back.