Not your run-of-the-mill alien movie.  More like Ghostbusters for the information age.
Actually, the plot is quite good.  It takes the legend of Men in Black (West Virginia was the site of a very famous MiB encounter, by the by) and turns it into a palpable comedy.

Blatant Plot Device Theft
1. Don't Touch the Red Button
2. Black/Urban/Witty/Smooth Guy meets White/Midwestern/Stoic/Old-Fashioned    guy.  Hijinx ensues.
3. Alien Body-Taker
4. Unlikely Hero saved from Bad Guy by Mentor from behind Bad Guy, who didn't see him there. (a.k.a. The Rock Syndrome)
5. Bad-Mouthed Alien Makes Funny

Plot Revelations About Life
1. The Tabloids have all the answers.
2. Men in Black have worn and must wear the same clothes that MiB have always worn...oh, except Will Smith...
3.  Alien Body Snatcher Rule of Etiquette #45:  Never let them see you decompose

the Acting: 
You have 5 of the best up-and-coming (and established) actors in the biz:
Will Smith, Tommy Lee Jones, Rip Torn, Linda Fiorentino and that whiz-bang computer thing.

the Action: 

the Good
Not too much, not too little.  Just the right amount in the right places.

Will Smith getting busted upside the head by an alien is good revenge for that ass-eating farce called Independence Day.

the Bad
I can't think of one dang thing.

the Ugly
Tommy Lee Jones gets intimate with an alien's esophagus.

the Directing: 
Barry's still cutting his teeth.