There a lot of problems with the EU honestly. This is a giant pile of different interconnected tales and books and comics and games from different creators. Some were close to each other, some not so much. Some are great read but contain something meh for overall universe logic, some are mediocre but safer and don't have out of place stuff. And answering this question is hard because there is something popular and great, for example, KOTORs, games that are good by themselves, however, they turned lore direction in a very meh direction and added a lot of bullshit and retcons that I not happy with, but to explain why and where you need to play/read all that crap to see the overall picture. In addition, there were after-retcons. Encyclopedia books, big official articles, tabletop stuff that tried to summarise, add and fix timeline which by themselves add to perception how you observing information in a new context. Most of the EU-assburgers are just constantly creating their headcanons and argue about everything on the internet. So this is what the EU is in reality: a giant half-organized pile of information where you creating your favorite universe. You can imagine it as Star Trek - classic shows are great, but they have crap and unconnected episodes.
So well, where to start... there are a bunch of great places. For example, something close to the movies, which would be nice without context.Star Wars Empire
- there was a bunch of comic series in the "main timeline" - from the old days of the republic to the far future, however, they came out in different times and there is no need to start from 35000years before. I like the "empire" series (not long before and sometime after Episode 4). Some of its arcs, like Darklighter, add to Episode 4 so much, that without this parallel story I can't imagine this movie at all, it feels unfinished without the story of Luke's best friend.Star Wars X-Wing Rogue Leader
- there was an actual X-wing Rogue Squadron comic series and books, but comic books are not the newest things and their stories contain a bunch of weird stuff. It is a fun read overall, but you may like to start from this prequel-mini series, set right after Episode 4. Short solid story connected to the movie makes a sort of introduction to the whole post-Endor situation, which in this universe ended in the fall of uni-galactic state and actual constant galactic civil war for years.Star Wars TIE Fighter
- 1994 videogame, part of the X-wing simulator series. This series of games is stuck between actual complex serious simulators and more arcade stuff, being more complex than wing commanders but not as complex as an actual flight sim, these series actually based on LucasArt's WW2 simulators. X-wing being the first game, TF was the second one and the best in the series. These games, using actual sources and existing at the time board games and EU tried to create a more serious, technologically depth approach to starfighters, ships, space combat, and tactics. TIE Fighter combining it with a deep political plot, showing galactic empire and its political and economical problems from inside. Set between episodes 5 and 6, it shows that this state was kind of doomed and without the rebels. The full CD version came out in 1995, in 1998 came out Windows hardware-accelerated textured version. The Windows version is broken as fuck, but you can fix it with wrappers, mods, and tweaking and it makes it the best version until the XWVM team will finish their remakes (not soon). If you are interested, I might post a guide.Star Wars Shadows of the Empire
- SotE was a multimedia project, created in times when Lucas came back to SW and was kind of part of "Special Editions" projects, expanding the story between Episode 5 and 6. Unlike mentioned above TIE Fighter, it focused on the main characters and main plot of the movies, in addition to a bunch of new heroes. The multimedia project consisted of a Book, a Comic series, and Videogame which add to each other. What I want to recommend the most here is the comic. I think, it is self-contained enough and you'll understand everything without additional sources and there is the most content that related to the movies and connects them. Game... well, I was not sold on the new character and its presentation and this is an N64 game. Meaning that story is just out of context chunks with quite primitive gameplay. 64MB limitation is quite hard for a 3d adventure plot-driven game, you may try it if you want. There was a PC version with creepy pre-rendered cutscenes instead of static art images from N64.Star Wars Clone Wars
- not 3d The Clone Wars, with is childish teenager cartoon where marry sue teenager girl and "funny droids" fight in 9000 boring seasons and which is now in Disney Canon so I dismissed it from EU because it was inconsistent with it anyway. I not a fan of prequels in general, their concept and presentation, however, this 2003 Tartakovsky's cartoon is what elevates them to a new, enjoyable level, where clone wars shown as epic galactic wars. From short original series, was compressed 2 complete movies, that will follow you right from episode 2 to episode 3 opening scene. This is one of the rare reasons why I tolerate Prequels' existence. They are available on youtube https://youtu.be/g6-yclEOgR4 https://youtu.be/t1LK-JwKt2I
Some scenes from here are pure platinum, real Jedi fights, real space army fights, highly recommended.Star Wars The Thrawn Trilogy
Well, this is the book trilogy most of us started from, a long time ago when EU was a mainstream, before dark, Disney times. And they actually nice adventures, with great scenes, great new additions to the universe, and a nice read overall. This is the sort of safe sequels many people wanted to, and I'm not surprised it still one of the most known and beloved Star Wars media pieces. Of course, I'll recommend reading it to a new person. However, this is one of the things I mentioned above, about where I think some stuff might be overrated, I have questions for a lot of characters and ideas on a universe level. Seeing that Thrawn's character was used by Disney for their morning cartoons and it incorporates everything worst I have complaints about for original books, making him some sort of caricature on himself. But more about it later, if you'll be really interested in all that crap, I'll make my giant wall of text especially for you, after you'll read all things mentioned below and above lol.Star Wars Republic Commando
- another star wars game set between 2 and 3 episodes, in clone wars. It is a nice atmospheric shooter where you are controlling the squad of Republic Commando clones in multiple missions. One of the nice and still known Star Wars games. There are RC books but.. eeh... even I didn't read them :\ Star Wars Empire At War
- the best RTS in a Star Wars series, have a campaign and galactic conquest modes, with a kind of total-war style galactic map. Standalone addon Forces of Corruption
is much better in my opinion - it adds 3rd side to galactic civil war, adds a lot of mechanics that make this game more deep and interesting to play. This game using a lot of EU stuff and addon elevates it to a new level. This game is from petroglyph, former Westwood developers. Zann Consortium music for addon was composed by Frank Klepacki.
You can ask me about any comic, or in general, things I mentioned. I have the great English scans of Omnibuses and what was translated on Russian for the most part if you need this also.