There is a scene in The Clone Wars where Ahsoka is in the middle of hallway, deflecting blaster fire from two directions while carrying on a conversation ("Cargo of Doom", I think) and it got me wondering...
In the original trilogy, lightsabers are mostly used for dueling - but we see Luke successfully ward off blaster fire with 100% success (amended: see Kyle Jones' answer... nearly 100%). He never gets hit.
In The Clone Wars, there are many examples like Ahsoka's where the Jedi are defending against an amazing amount of blaster fire. Often from multiple angles. Usually while talking.
But in the prequels, we see the defense effective - with the notable exception being when Sidious starts speed dialing Clone Troopers to murder Jedi:
Even then:
- Master Mundi is clearly shocked at the betrayal and not defending himself fully
- Secura is shot in the back while she is unarmed. Repeatedly.
- Plo Koon is shot down while in a Starfighter
- A Jedi is killed by speeder bike cannon fire (no lightsaber involved)
Obi Wan and Yoda make dramatic escapes. We basically see one lone nameless Jedi get gunned down in what looks like a fair fight. While conjecture might assume there were many more... what we see onscreen is that the best chance you have to beat a Jedi that is ready and armed with a lightsaber is to bring a cannon.
Are there other notable times when a blaster beats a lightsaber?