My recommendation of must watch old movies:-

1) The Thing (One of the best horror movies from the 80's)
2) Nightmare on Elm Street (The first one is the best, the rest you can skip)
3) Halloween (again the first one is the best, the rest you can skip)
4) Ferris Bueller's Day Off (best ponteng school movie)
5) Stand By Me (I think it's still the best movies about growing up)
6) Goonies (Very good children adventure movie)
7) Gremlins (Still one of the best monster comedy movies)
8) Top Gun (Still the best aerial combat movies)
9) Platoon (I think this is better than Apocalypse Now)
10) Beverly Hills Cop (best Eddie Murphy action movie)
11) Beetlejuice (Very good horror comedy)
12) Weird Science (Kelly LeBrock at her best)
13) Mannequin (Kim Cattrall before her days of Sex & City)
14) Poltergeist (watch only the first one, the rest do not watch)
15) American Werewolf in London (I still think this is the best werewolf movie)
16) Spaceballs (If you're a fan of Star Wars, you must watch this movie)
17) Dirty Dancing (I prefer Patrick Swayze in this movie than Ghost)
18) Neverending Story (one of the best children movies)
19) Rocketeer (Jenniffer Connely at her best)
20) Untouchables (One of the best Kevin Costner movies)
21) No Way Out (One of the best Kevin Costner movies)
22) Dances with Wolves (One of the best Kevin Costner movies)
23) Footloose (Still one of the best dance movies of all time)
24) Short Circuit (A very good comedy about robot)
25) Highlander (The first one is the best, second one OK, the rest you should skip)
26) Willow (Underrated George Lucas movie)
27) Legend (Underrated Tom Cruise movie and Mia Sara is in this movie)
28) The Adventures of Backaroo Banzai (Not everyone will like this movie)
29) The Last Starfighter (One of the better sci-fi movies during Star Wars hype)
30) Enemy Mine (Really underrated sci-fi movie)
31) UHF (Weird Al Yankovic)
32) Hot Shots (Really good spoof comedy from Charlie Sheen)
33) Color Purple (A very good Steven Spielberg movie a lot of people forgotten)
34) Empire of the Sun (A very young Christian Bale movie)
35) The Lost Boys (Still one of the best Vampire movies of all time)
36) Wall Street (Greed is Good)
37) Dead Poets Society (Robin Williams at his best)
38) Commando (I dunno why but I prefer this than Rambo)
39) When Harry Met Sally (The orgasm scene is still unforgettable until today)
40) Final Countdown (A very good "what if" story)
41) Das Boot (Must not miss if you're a fan of submarine)
42) Big (Tom Hanks as a naive 13 year old)
43) Body Heat (Kathleen Turner when she's super hot)
44) Romancing the Stone (Some say its a poor imitation of Indiana Jones)
45) Jewel in the Nile (I think its better than Romancing the Stone)
46) 9 1/2 Weeks (Not family friendly movie)
47) Blue Velvet (Another not family friendly movie)
48) Last Emperor (One of the best movies about China made by westerners)
49) Escape from New York (Underrated 80's action movies)
50) Big Trouble in Little China (Another underrated 80's action movies)