I believe The Beatles: Rock Band came the closest to being perfect. Eveything about that game was just beautifully done and the only things missing was Pro Drums, an option for Keys, and a few more Beatle songs (Hey Jude, Strawberry Fields Forever, Yesterday etc. etc.)
The original Half Life is pretty fun, but I’d recommend checking out Black Mesa. It’s a remake of the original game in the same engine that Half-Life 2 uses, and changes some things for the better.
I kind of feel like part of what made Half Life special was the historical context in which it was released, and what they were able to do with the technology of the time. I think you lose a lot of that by just jumping into Black Mesa.
That said the original Half Life hasn’t aged as gracefully as Half Life 2 (which holds up very well in my opinion)… So I can see why people recommend this.