Try these:

Deathrace 2000 with David Carradine as "Frankenstein" - you basically get points for killing people on the road with your car as you race to the finish.
Dead Alive - One of the best period gorey zombie films ever made (another Peter Jackson film) - "I kick *** for the Lord!"
Sean of the Dead - recent Brit parody of the zombie film - actually quite good.
Bubba Ho Tep - Elvis was replaced by an impersonator (who dies - everyone thinks it's the Real Elvis but it's not) and ends up in a retirement home, that's being terrorized by a soul sucking egyptian pharoh. Some great dialog in this one.
Mad Max and the Road Warrior - the AU cuts of each film if you can find them.
Nightmare Before Christmas - Tim Burton at his best.
Blue Velvet and Dune - David Lynch's bastardized cousin films. I recently bought the extended version of Dune - fairly boring stuff compared to the theatrical cut but interesting in its content.
Rushmore - if you haven't seen this I think it's worth a rental.
Crouching Tiger Hidden Dragon - an incredibly beautiful film - I still thrill in viewing (and I've probably watched it a dozen times).
O Brother Where Art Thou? - another must view.
Actually, pretty much anything by the Cohen or Farrelly brothers are worth a look-see.

I'll let you guys decide if those are "best" or "worst"

-- John