A few rides that I haven't seen mentioned (I dont think anyways). These are in the past 10 years, the ones that I remember watching
2005 Giro Penultimate day, Rujano, Simoni and Di Luca attack on the gravel road of the next to last climb, had a 2 minutes lead at the top. By they time they reached the base of Sestries, Paolo pulled back almost a minute and half, and was able to hold onto the maglia rosa by around 20 seconds.
2003 Paris-Nice Stage 4, Finish on top of Mont Faron, who can forget Vino winning the stage (and the race ) brandishing a picture of Kivilev at the finish line 2 days after his death.
2003 Giro Stage 12-The Finish on the epic Zoncolan, Simoni winning the stage over a 2 man chase group, which included Garzelli and his ex teammate Marco Pantani. Unknown at the time, this would be the last time we would see Pantani be a factor in a stage of a Grand Tour.
2004 Tour De France Stage 13- Sometimes the greatest rides are based on pure survival. Finish in PLateau de Beille, who could forget Voeckler in yellow falling off the back of the peleton every climb just to chase back on. Then in obvious agony, pulling himself inside out and his infamous reaction at the finish when he realize he held on to yellow by a handful of seconds. This to me will always be considered epic.
2006 Stage 17 Vuelta a Espana- A downhill finish in Granada. VIno and Kash 1 and 2 on the top of the final climb, Valverde chasing behind in the golden jersey. Valverde gets to within about 5 seconds on teh descent when Vino takes off for what appears to be a last gasp effort. He hooks up with Tom Danielson and Valverde fades back. Danielson wins the stage, Vino wins the Vuelta.
I dont mean to neglect the classics, these stages are the first ones that came to my mind. Most of the classics I can think of, are ones already mentioned. The one classic I can think of that I dont think has been mentioned be
2008-Het Volk- Gilbert solos off the front of the group with 50km to go and goes through the breakaway, then finish solo to win the Classic.