Let the hive mind of Engadget get that for you.
"As someone who doesn't reside in the USA, I was wondering what would be the best way to get internet for my computer in the US for a couple of weeks? If it were Europe I know I'd look for some prepaid data. Is there anything similar offered by American carriers? A MiFi or a data SIM that I can tether from would work, but I'm trying to maintain a tight budget. Help!"
Seems like a big jump for just a bigger hard drive, slightly different remote, and the George Lucas tax. I upgraded my ordinary TiVo HD with a bigger drive and got a Harmony One remote for a similar cash outlay. It's not THX certified, but then I have given George Lucas enough money on other THX stuff to know I'm not missing out.