My favorite match of all time is Dreamer vs. Raven at Wrestlepalooza 1997. I also love RVD vs. Lynn from Living Dangerously 1999, Angle vs. Benoit from The Royal Rumble 2003, and Samoa Joe vs. AJ Styles from Sacrifice 2005.
My favorite ROH match is a tie between Punk vs. Joe 3 from All Star Extravaganza 2 and Danielson vs. 'Cide from Final Battle 2006. Raven vs. Punk (Death Before Dishonor), Joe vs. Kobashi, Styles vs. London (Night of Grudges), Styles vs. Danielson 1 (Main Event Spectacles), Danielson vs. Alex Shelly (Arena Warfare) and Danielson vs. Jimmy Rave (4th Anniversary Show) are some of my other favorites. If I started rambling off Briscoes matches, I'd be here forever, but if you're ever looking for a fun match, watch anything with them.
You'll get plenty more of my ROH taste once Harthon gets off his lazy ass and continues his ROH year in review threads.