Sioux Falls, mentioned above, is actually not in Nebraska. It's in South Dakota. Don't confuse it with Sioux City, as many people do--they are 60 miles apart.
Lincoln is a college town, and so there ought to be some gamers there--I'm not sure about gaming shops in Nebraska, but if you're willing to drive up I-29 for an hour and a half, the only shop worth a darn in Sioux Falls is the Dragon's Den, just off Louise Ave. Nonetheless, Omaha should have something, as it is the biggest city in the area.
As a native midwesterner (now living on the east coast), I can say definitively that compared to everywhere else, Nebraska is flat. There are some low, rolling hills in isolated parts of the state, but there are also huge tracts of land so flat that you can SEE THE CURVATURE OF THE EARTH.
PC, should you visit, you'll not want for cornfields, but soybeans have been taking more and more acres, with corn moving north into the Dakotas and Canada, and South toward Kansas.
Sorry I couldn't help you more--I'm a South Dakota native, so I can only comment in general terms. It's a great place to live, with friendly, polite people and great food. The biggest difference is that things are rarely a big deal to people in the midwest--they don't freak out at anything. Blizzards, tornadoes, etc. are just everyday ocurrences, depending on the season, and so you never see people fighting over the last bag of flour in the grocery store, because they think that this is the END OF TIME.
