As a warmup, here is a link to the CQ House map, which is color coded to show how competitive congressional districts are around the nation. Note that CQ rates 29 of the 433 House seats as "toss ups" and that of those 29, two of them are right in our own backyard -- Tennessee's 8th Congressional District (Democrat Roy Herron vs. Republican Stephen Fincher) and Mississippi's 1st Congressional Districts (Democrat Travis Childers vs. Republican Alan Nunnelee). Both are currently held by Democrats, but Republicans believe they can win them. Both are mostly rural with some urban and suburban areas. And both will be receiving lots of attention from media and political donors from across the country.
Also worth noting -- two of the 31 "leans Democratic" districts are across the river in Arkansas -- AR-1 and AR-2, both currently held by Democrats.