A quick look at the first four games:

Maryland vs. Miami For some reason, I think Miami has the greatest potential for an upset. They've slowly gelled into a real team since suspending Denis Clemente for the remainder of the season. They've taken their last two opponents - both bubble teams fighting for a postseason - to overtime, McClinton is showing the promise he had at the start of the season, and Brian Asbury as upped his rebounding and become a real force inside.
Their defense has even gone from a horrid 1.20 opponent's point per possession through the first 10 games to a more respectable 1.12 in the last six. They even managed to win two of those games.

Unfortunately, they're up against the one team unlikely to treat them lightly. Maryland is the hottest team in the conference at the moment, having recently backed up D.J. Strawberry's famous rhetorical question about winning the last seven games of the season. The Terps lost their only game against the Hurricanes back in January, and should have significant motivation to keep history from repeating. But they did just string together that seven-game winning streak, and there's a chance of a mental lapse. Miami has a surpisingly potent offense for their record, and I think they can pull off the 12th-seed shocker.

Duke vs. N.C. State You know, if they played this game first, they wouldn't have to bring out the extra chairs for bench players until the second game. Yep, it's the matchup of the two teams with no depth, slow tempo, and less than potent offenses. Only the Wolfpack are running on fumes, having not put together an impressive half since the first twenty mintues of the last UNC game. Duke still has a strong defense, even without the infamous Gerald Henderson, and I can't see the Wolfpack pulling this one out.

Georgia Tech vs. Wake Forest No team shuld lose to Wake Forest. Of course, Georgia Tech has managed to do so once already, and only won one conference game outside the confines of Atlanta. I'm still not sold on them getting an NCAA bid. They're 1-9 on the road this season. One win in ten tries! It's horrific. That one win was in Florida though, so maybe they can avoid embarassment in Tampa as well.

Clemson vs. Florida State Ah yes, the NCAA play-in game. The Tigers have put together their first two-game win streak since they were undefeated, even if one of those games was an overtime win against Miami, which probably shouldn't count. FSU has a similar streak of unimpressiveness, with two wins over N.C. State and Miami (again, in overtime) erasing the five game losing streak that proceeded it. They do have Toney Douglas back from injury, though, which should help.

On the merits, the game should probably go to Florida State. Their potent, occasionally solely Al Thorton generated offense, makes up for their dismal defense. Clemson has slipped to average on both sides of the ball. So if I have to pick a horse to back, it's the hometown favorite. The important thing is neither team looks to be a threat to the Tar Heels in the next round.