Top 5?
Ether
Who Shot Ya?
The Ripper Strikes Back
No Vaseline
Hit Em Up
That's tough man because some of the best diss tracks ever have been on some lesser known beefs...so I'll do 2. 1 list of shit y'all of heard of and 1 you probably haven't.
Heard of:
1) Ether - When Ether dropped, most hip hop fans can tell you where they were the first time they heard it, like 9/11, the kennedy assassination, moon landing, etc. Everyone thought Nas was cooked after Takeover, which probably makes a list like this if Nas didn't drop this nuke to respond to it.
2) No Vaseline - In retrospect, this was the beginning of the end of NWA.
3) Hit'em Up/Who Shot Ya - I was never a big Pac fan, but if he smashed Faith Evans and then rapped about it, he wins. It's alleged to have never happened...then he's lying on his dick and loses. Both are dope songs though.
4) Drop A Gem on Em - So uhhhh, most people overlook this track as Mobb's response to hit'em up. This was a monster, monster diss record. It references a rumor that Pac got raped in Riker that Pac had to address in public after this.
5) Checkmate/Problem Child - Context is important. 50 was the biggest thing in the universe at the time and had spent the better part of 5-6 years beefing with everyone and had just finished ending Ja Rule's career as a star. Dude started his career with a diss track aimed at the entire industry, just all day every day beefing with people. Considered unfuckwithable. Said a few things about The Lox though and Jada fucking crushed him.
Bonus #6) Bitch in Yoo - Everyone thought Common was just a nice guy concious rapper from Chicago, lol fuck. The same guy who smacked NWA around got handled by the 'Ressurrection' guy?? This was like the Wayne Brady skit happening but in real life.
Maybe haven't heard of:
1) Freddie Gibbs - Real . At Jeezy
2) Royce - Malcolm X . At D12 mostly, 50 kinda, and Eminem subliminally
3) El-P - Linda Tripp. An old old Def Jux era beef with Anticon. Considered the best diss track from the era/place that more or less birthed "backpack rap"
4) Common - stay scheming (jacked Drake's beat to diss him with). Drake didn't learn from Cube's mistake apparently. Leave that nice man from Chicago alone.
5) Masta Ace - Acknowledge
Bonus #6) Cormega - Fuck Nas & Nature .....yeah, that's kind of what it is. Call this whatever you want, you can't call it sneak dissing.