My 5, which are all still classics to me even now:
Depeche Mode - Violator. The First album I ever heard and loved. That was years and years ago, and even now, I still think it's a classic. Hard to describe the kind of feelings I get when I listen to it, but it's some of the best 'mainstream' music that's out there. Dark, polished; DM's masterpiece.
Porcupine Tree - In Absentia. Not only PT's best album (IMO), but my favorite album of all time. Period. I first heard it in the car with my Dad; he forced it on me (rightly telling me that it was a masterpiece) and it didn't even take 30 seconds for me to be floored by what I was hearing. I had no experience with anything 'heavy' up until that point (I had just started middle school), so IA served as my gateway to pretty much all the music I listen to now. The album itself is... stunning, not to oversell it. Such a fantastic blend of different styles and genres; the songwriting is extremely tight; every member's contributions are fantastic; the atmosphere is amazing; and, most of all, it's an
album - the sum of the music is greater than it's parts. Every emotion is explored; different genres are all showcased and blended seamlessly together... it's linked by (what I think is) a very intriguing concept, serving as a 'thread' to unify all the tracks... Collapse the Light into Earth is a song I can cry to (not even kidding!)... etc. Amazing album; highly recommended for ANYONE who hasn't heard it.
Opeth - My Arms, Your Hearse. Absolute classic; the group's magnum opeth (haha, I'm so funny). Once again, music that came into my life during a pretty turbulent time; thus, it emotionally connects with me in a way few other albums do. It was the first true 'metal' album I ever loved, and it's quite possibly my favorite metal album ever, to this day -
maybe. Once again, it's another case where no track is worth skipping (they're all great); Mikael's vocals are the best of his career, IMO; Karma is the best song ever, etc, etc. The atmosphere is something to write home about, too... very thick and ghostly; fits the concept (and the brilliant lyrics) perfectly. MAYH impacted me so much because it continued to propel me forward musically; opening new doors, introducing me to new concepts, and so on and so forth. Oh, and did I mention Karma is the best song ever? The outro is an out-of-body experience...
The Mars Volta - Frances the Mute. A little over a year ago, I finally took a leap of faith and bought De-Loused in the Comatorium, hearing so many good things about TMV online. Loved it, predictably; so I took another leap of faith and bought Frances the Mute, once again having heard all the praise for it... and my mind was absolutely blown. This was another case of 'hundreds of doors flying open' upon hearing it for the first time; I didn't even know what to think after it ended. It's a perfect album, as far as I'm concerned; everything and everyone's performance is flawless; every song... just ridiculous. Even the 32 minute Cassandra Gemini (NO THERE'S NO LIIIIII-IIII-IGHT) is just perfect. A lot of people don't care for the (long) ambience in between tracks, but I love it - makes the album feel even more like the conceptual 'suite' it was intended to be... almost like watching a movie. Can't really say much more about it, because I can't do it justice - very dense, very cerebral, very emotional, VERY high quality, engaging, fantastic, flawless album. Miranda That Ghost Just Isn't Holy Anymore gets a special mention for it's
gorgeous ambient intro, and the heartstring-tugging sections that follow.
Devin Townsend - Addicted. The album that introduced me to Devin, as well as the one that opened the last remaining 'doors' for me, musically. The perfect mix of aggression and poppy euphoria on every single track; the level of
quality every song reaches is incredible. Currently my favorite Dev album (not counting Strapping Young Lad) if only because I think it's the strongest set of compositions he's ever put together on one record. As I said, every song is great, but Awake!! just takes it to the next level for me - one of my all time favorite songs ever. Whole album kicks ass; can't say much more about it.
I guess the hardest part through listing and describing all these, for me, is that I can't describe the feelings I get (and have) when it comes to these albums. They're all great to me, and they all mean a hell of a lot to me emotionally, too... it's just hard to describe the 'experience' I've had and have when it comes to hearing them.
So, TL:DR; Depeche Mode's Violator; Porcupine Tree's In Absentia; Opeth's My Arms, Your Hease; The Mars Volta's Frances the Mute; Devin Townsend's Addicted. That's where I currently stand; they're all fantastic.